Coil Master is the first thing that pops into my head whenever I think of coils and DIY vape building.coil master 521 plus ready box review

I mean let’s face it these guys pretty much nail the tools and gizmos they bring out with any serious builders owning at least one of their products.

Coils Cotton and the Coil Master 521 Plus Tab – Ready to Build?

The company’s 521 Plus Tab is a recent recent release that underneath that cool styling packs a raft of features.

The latest addition to the Coil Master family is the Ready Box – a nifty little tin that contain x6 pre-made coils and a wad of pre-cut and pre-sized cottons trips.

So two really useful tools for the DIY vape builders out there – so have they helped me on my journey as a relatively new builder?

Let’s take a closer look.

As always my thoughts and opinions are my own.

First up the Coil Master 521 Plus Tab.

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Inside the Box


Very smart box with everything packed away neatly inside:

  • 521 Plus Tab x1
  • Voltage meter part x1
  • Alligator clips x2
  • USB cable x1
  • Manual x 1


  • Ohm meter
  • Coil rebuilding deck
  • Coil burning
  • Reverse battery protection
  • Short circuit protection
  • Battery output voltage testing
  • Able to work with single or dual batteries

in hand


  • Resistance Measuring Range: 0.03-9.9ohm
  • Resistance rate: 0.1ohm
  • Connection: 510 threaded with spring loaded pin
  • Charging: 5V/800mah Micro-USB
  • Battery: Single or Dual 18650 battery driven (Battery is not included)
  • Automatically power off in 15 seconds while burning coil
  • Dimension: 130mm x 130mm x 30mm
  • Weight: 290g
  • Housing material: ABS & Zinc alloy

Key Features

The all new, and it has to be said very cool looking, Coil Master 521 Tab has multi functions.

You can of course use it as an extremely stable build platform with the spring loaded 510 taking pretty much any deck you care to throw at it.

voltage checker

You can test the resistance of your coils – dry burn them and using the battery voltage check adaptor you can test the battery output and voltage.

There’s also a couple of leads with crocodile clips that you can use to test your coil resistance before adding them to your deck.

crocodile clips

The Tab is powered by both a dual and single 18650 and also via the USB port and can go from from fire mode to resistance mode at the flick of the switch.

There’s a magnetized section on the side which is a handy little addition to keep those stray coil legs safe before disposal.


Despite the size of the 521 Plus tab – the screen is tiny and not the brightest you’ll ever see.

Design and Build Quality

As you might expect from Coil Master the finished product is both stylish and beautifully made.

There are no moving parts as such but the clips and the voltage checker fit into the holes perfectly.

521 tab plus

Design wise it has been likened to a UFO however I think it looks like one of those curling stones.

It’s quite light for its size but being so wide does mean you have a really secure deck to build on and the large rubber grips on the base means this won’t be moving around.

Look this is night and day to the previous versions and indeed in my opinion to other ohm readers out there as this is both multi-functional and extremely stylish.

How Does the Coil Master 521 Plus Tab Perform?

It has to be said this is a solid piece of kit that does more than most of us will ever need it to do!

The extremely basic comparisons I’ve made using the 521 Mini Tab shows it appears to be as accurate if not more so – in a few resistance readings the 521 Plus read slightly differently.


As you can see from the earlier photos the voltage checker works well as do the crocodile clips used to read resistance on coils before added to your deck.


The only issue I and indeed many others have noticed is the screen is tiny and certainly not the brightest you’ll ever see which is a real shame given that’s the most important part of the device!

What I Like

I like the size and design very much and it really is a solid base to build on.

The huge ring fire button is excellent and extremely responsive and that little magnetized feature on the side is very good indeed to keep your wayward wire legs stored.

As I’ve already stated it can be operated in single and dual battery mode and depending on your build it actually gives a decent vape – speaking of the batteries the compartment is extremely clean and the magnetized door is snug with good venting.


What I Don’t Like

Apart from the tiny dim screen there’s not a lot to dislike.

There’s a lot of advanced features that some of us may never use but hey at least they’re there if you need them.

Final Review Verdict

It does exactly what it says on the box and a whole lot more.

Design wise I absolutely love it and as a building deck it is fantastic with plenty of room and is solid with absolutely no movement no matter how hard you might be wrenching your coils.

Another winner from Coil Master!


  • All the bells and whistles you’ll ever need to be a master builder 😉
  • Great design
  • Solid construction
  • Dual or single battery
  • Firm foundation to build


  • Screen is tiny and dim

The Coil Master Ready Box Reviewed

Next up a handy little tin filled with x6 pre-made coils and a ton of pre-cut cotton strips.

Inside the Box and Specs

  • Coils x6
  • Cottons x12
  • Manual x1
  • Weight: 54g
  • Packing: Tin box

ready box

OK this is handy little piece of kit for vapers on the go.

You get a nice sized tin containing pre-cut cotton strips and a total of 6 coils:

  • Fused Clapton 26*2+39AWG 3mm NI80 0.3ohm
  • Clapton Parallel 26*2+39+26 AWG 3mm NI80 0.3ohm
  • Triple Clapton 26*3+40AWG 3mm A1+NI80 0.25 ohm

ready box contents

Now I’m no coil expert but they look well-made though one of mine did have a long thread from one of the legs – I simply snipped it off with no problems.

I have used all three coils in my trusty old Doge III and they do indeed read the resistance stated.


I haven’t used NI80 coils before and despite the name they are NOT designed for temperature control – so power only – although my understanding is if your mod has a setting suitable for NI80 then by all means use them in temp control – but do double check first!

I’m not a great temp control user so these were only used for the purpose of this review in power mode.

How Do the Coil Master Ready Box Coils Perform?

Despite the low resistance the beauty of NI80 coils is they don’t need as much power to ramp up.

I found that all three coils were pretty much instantaneous and despite instinct telling me otherwise I was able to get a very warm vape at relatively lower power between 50 and 70 watts.

coils glowing

I felt that I got – surprisingly – more vapor and flavor from the Clapton Parallel than the others which given I seem to use a lot of Fused Claptons was indeed a surprise.

Manipulating them on the deck was a little tricky as they aren’t the most robust so none of that wrenching about else as I found with one particular set they will lose their shape easily.

What I Like

I love the presentation – that box is extremely handy once empty for all sorts of vaping bits ‘n bobs.

The stiff foam material the coils are bedded into is good too stopping them from moving around and useful for storing others when you’ve used these.

coil master cotton

The cotton is not the best I’ve ever used but it is OK and cut to pretty much the exact size of the coils which is an added bonus and there’s plenty in there.

I like the price too – x6 decent coils and a lot of cotton for less than ten bucks – bit of a bargain!

What I Don’t Like

Again not much to dislike however the choice of NI80 might put some folks off – however I enjoyed the super-fast ramp up time and the need for less power.

Final Review Verdict

It’s a nifty little kit inside a super useful tin with everything you need to coil and wick.

Well-presented and at a good price I would maybe like to see different wire options available such as Stainless Steel and Kanthal.

This is ideal to pop in your bag or suitcase or leave in your car so you’ve always got a backup when out and about.

So yeah the Coil Master Ready Box gets a nod from me.


  • X6 coils
  • Pre-cut and sized cotton
  • Useful tin


  • NI80 wire MAY put some folks off

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Coil Master 521 Plus Tab
Coil Master Ready Box
I have simpler vape tastes these days - I never leave home without a Caliburn G, a Vaporesso Luxe 40 or Innokin EQ FLTR and a CBD vape pen or bottle of CBD drops in my rucksack...or indeed an Aspire Nautilus Prime X in my pocket... At home I'll be using various mods topped with the GeekVape Zeus X RTA or the Signature Mods Mono SQ topped with the Augvape BTFC RDA... I'm a former journalist and now a writer and sometimes author... I'm ex Army - adore dogs and never happier than hiking over the hills or with a good book on a beach.


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