SX Mini M Class by Yihi – Does The Performance Match The Premium Price Tag?

The follow up to the SX Mini S Class, rated by many as one of the most functional and ergonomic personal vapourizers ever to hit the market, and powered by an excellent Yihi chip it did very well at the higher end of the market.Yihi SX Mini M Class

Manufactured by Yihi themselves, a renowned chip maker within the industry responsible for providing the chips that power many popular mods, the follow up to the S Class is the M Class, featuring the brand new SX350J chip, which now features temperature control amongst a slew of other features and performance upgrades, and although the S Class was already one of the most ergonomic mods around Yihi weren’t happy with it and have refined the body further still!

Made from the highest quality materials, with one of the most highly regarded chipsets and one of the highest price tags on any widely available unit so far, does the Yihi SX Mini M Class live up to its price tag??

What’s In The Box?

This is probably some of the nicest packaging you are ever going to come across with any device you buy. There is a real premium feel to it, right down to the boutique white laminated string handled paper bag the SX Mini M Class packaging comes in, down to the white box you find the unit housed in. Inside this little box you will find-

1x SX Mini M Class
1x USB Cable
1x Instruction manual

Battery / Body / Build

It’s a work of art and a testament to design quality. Taking a lot of cues from the S Class, but reducing the overall size slightly and rounding off the edges, you probably won’t hold any other device that seems to seamlessly fit into your hand as well as the SX Mini M Class does.Yihi Mini M Class colours

In terms of build quality, the manufacturing is pretty much unmatched by anything else available, Yihi have spared no expense when it comes to the build quality of the M Class but there is one small issue that has been reported- the paint quality of the finish around the outside of the device.

Essentially, a lot of devices have had reports of the paint finish scratching off, which I haven’t experienced personally with my device. You can purchase a case separately should you wish to protect the finish, which for an outlay of a few pounds is well worth it to protect the quality of your very expensive M Class device. This is disappointing from Yihi and you would expect the paint finish to be better.

At the top of the SX Mini M Class you find a 23mm polished and plated stainless steel connector, with a floating 510 pin that will handle any atomiser you screw into it with a 510 fitting, and look absolutely seamless at the same time.Yihi SX Mini M Clas Review

You have stainless steel buttons for the power and plus and minus buttons, and these have to be the most solid and responsive buttons I’ve used, with next to no button rattle. There is a micro USB port for charging and also upgrading the SX Mini M Class firmware as well.

There is a battery cap present on the bottom of the device, that is operated via a coin, and this is just buttery smooth, I have had no issues at all with the threading, and battery swaps are made quick and easy with this.

SX Mini Battery compartmentYou have an OLED screen present on the device, which provides some of the most comprehensive information whilst still remaining concise. On the screen itself you have information on your current battery status, real time battery voltage, resistance, battery level, selected power mode and in temperature control mode, you have your selected temperature limit displayed, which shows you the real time coil temperature when in use, and instead of a vape timer you have a joules per second counter.

The SX350J firmware is upgradeable, and there is an upgrade already available for download that gives you extra power plus support for Titanium wire builds.

SX Mini M Class Features

Pull up a chair and get comfortable, as the SX Mini M Class is absolutely jam packed with features, and here is the lengthy list-

  • SX350J chip
  • Joules temperature control mode, max of 60J
  • Temperature range 200-580F, 100-300C
  • 60w power output with single battery, 120w using a separate battery extension
  • Four modes- Powerful+, Powerful, Standard, Soft
  • Buck-Boost & Boost, DC-DC Converter
  • Ergonomically designed
  • Micro USB charging port available
  • Reverse polarity, short, low resistance, low battery voltage and overheating protection
  • Bypass mechanical mode available
  • Stainless steel buttons
  • Lightweight, high quality aluminum body and the highest quality build materials
  • Firmware upgradeable, support for Titanium builds available with upgrade
  • Output voltage 1.0-9.5V
  • Gravity sensor to adjust settings

SX Mmini M Class Temperature Control

It’s the best of the best when it comes to temperature control, I haven’t experienced a chip that performs as good as then SX350J one does.

You need to use Nickel wire (or Titanium can be used in temperature control with the SX Mini M Class through a firmware update), and you also need to ensure Joule mode is selected through the menu, and your base atomizer resistance is set when both the atomiser and M Class unit are at room temperature, to do this hold down the plus and minus buttons until your atomiser resistance is displayed. Temperature limit is also set through the menu.

Resistance down to 0.05 ohm is supported in temperature control, Yihi do recommend that a build of 0.065ohm will provide optimum performance. This essentially means that you do not need as many wraps with your build so your coils will heat up quicker and perform far more efficiently than they would with other temperature control devices that have a higher minimum resistance.

The result is one of the smoothest tasting vapes you will experience, and no more dry hits!

A ‘dry coil- no liquid’ message is displayed when you coil has become dry to protect against dry hits and to note I have never once experienced a dry hit when using the SX Mini M Class!sx-mini-screen

How Does The SX Mini M Class Perform?

The SX Mini M Class writes the book and the definition on performance. I haven’t experienced anything that performs on the level of the SX Mini M Class.

It’s not the most powerful mod by any means, without upgrading you have 60w in power mode and 50J in joule mode available, but the reliability and the accuracy of the M Class is simply unparalleled. It’s not going to seize up on you, it does what you ask of it every time.
Chip efficiency is reported at close to 95% which makes it one of the most, if not the most, efficient chip available. In temperature control mode, builds are supported down to 0.05ohm, though Yihi recommend an ideal resistance of 0.065ohm, meaning less wraps with your coil to achieve maximum performance.

Battery life isn’t amazing given it is powered by a single 18650 battery, but it is a lot better than the majority of single battery 18650 mods available. You can get a full day’s vaping out of the SX Mini M Class as long as you haven’t maxed all the settings out.

The menu system is easy to use, and very user friendly, accessed with 4 clicks whilst the device is unlocked. At first, you might be overwhelmed by the sheer amount of available options, but you will find you very quickly adapt to what is available.

Tilting the device left and right utilizes the gravity sensor to adjust the available options, this can be turned off with a firmware update. Power output, power/joule mode, bypass mode, link mode, temperature limit and temperature unit display can all be adjusted here.

5 preset adjustable power settings can be accessed with through the menu system, so you can select and save your favourite power settings for easy access.

The SX Mini M Class can be locked rather than powered off if you wish for quick use, you simply click the power button three times to lock the device, three clicks unlock it.

You have four power boost options also available (five with a firmware upgrade that adds Eco mode), soft mode will decrease the selected power for a couple of seconds before it returns to normal, standard offers power output at the selected power, powerful gives you a slight boost to your selected power for two seconds, powerful+ mode boosts the power by 10% for two seconds, making pretty much all your builds ramp up almost immediately!

Performance can also be boosted by buying a separate battery extension tube, allowing you to use two 18650 batteries, and power is then boosted to a max of 120w in power mode.

There is just nothing that performs better or more efficiently that I have experienced than the SX Mini M Class.

Final Verdict

A truly outstanding, groundbreaking device from Yihi. If you are looking for a mod that has it all, the M Class is right up your street. It really does live up to the hefty price tag, and if you were ever looking for that one really special device, the M Class is for you.

It looks incredible and the performance is completely unmatched, there isn’t anything out there that can even get close to how good the M Class really is. Truly on a different level to anything else available, and you may not need to ever buy another device again should you purchase one!

The Good

  • Bar the paint flaking issues on some units, the build quality is outstanding
  • Ergonomically fantastic
  • Incredibly reliable
  • The best temperature control mode around
  • Wealth of different options available
  • Excellent menu system
  • Incredibly accurate
  • Looks amazing
  • Additional soft, standard, powerful and powerful+ modes allow you to really fine tune your vaping experience
  • The best buttons I have ever experienced on a device
  • Buttery smooth threading
  • Screw in battery cap is excellent
  • Firmware upgradeable

The Not So Good

  • Price isn’t going to suit everyone’s budget
  • Paint finish has a tendency to flake off
  • Battery extension looks ridiculous, not something you would take out with you!
  • Battery life can be a little limited with a single 18650 battery- though still seems to last a lot longer than most other single 18650 devices, down to the excellent chip efficiency
Build Quality
Ease of Use
Been vaping full time for three and a half years, started on cigalikes for a fair while then curiosity got the better of me and I moved onto an ego/ce5 set up after, a month or two later I was seeing people walking around with these interesting shiny tubes and I thought 'I gotta get one of those'. Before I knew it a trip down to my local B&M got me my first VW mod, an Innokin SVD, paired with an iClear 30, and I was hooked. Soon after that I was jumping to VW mods both box and tube shaped, before I then made the jump to rebuilding and thus sub ohming, with my first RDA and mech mod. These days I'm still preferring mechanical mods, but using VW mods with both RDA's and tanks alike whilst on the move, most importantly I am still loving vaping!


  1. Absolutely love the sx mini, fantastic build quality and feel in the hand. I’m a fan of the yihi chips, I’d say this is probably the best they have produced. 9/10 from me, would highly recommend.

  2. Hi Ratamahatta,

    Great review of the Yihi SX Mini M Class!

    Are you aware of any intention by Yihi to extend their upgrade/download facility to Macs, and when, as I have a preference for Ti.


    • Thanks Pete!

      I’m not aware of Yihi offering Mac compatibility for now, their website still says it’s windows only, they have the SX Mini ML Class coming out shortly which they are concentrating on, this will include temperature control functionality for Ni200, Ti, Stainless Steel and even Silver and Gold wire as well out of the box.


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