Coil Master has managed to establish itself as an important company in the vaping industry with top of the line accessories. Coil Master’s impact in the vaping world is quite important as they have offered us a better and quicker way to build. This is mainly due to the release of some interesting products, out of which I would like to mention the Coil Master DIY Kit V2, that I have reviewed a while ago. In  today’s review I will also be featuring other accessories from Coil Master however the focus will be on this little tool – The Coil Master 521 Tab.

What is a Coil Master 521 Tab?

The Coil Master 521 Tab is essentially a multi-function tool  that enables you to rebuild coils for your atomizers in a safe and quick way. The fact that it is so versatile it will certainly make it even more appealing to take it away with you, this tool ca replace all of the below in a small and compact package:

  • An ohm reader
  • A voltage meter for mechanical mods/regulated mods
  • A coil rebuilder/testing deck
  • A table Mod

Box contents

Coil Master 521 TabPackaging for this device looks top notch, the device arrived in an eye appealing red and black presentation box with the Coil Master logo embossed on the top of the box and 521 lettering on the sides. All the accessories are nicely tucked in and easily reachable.


The box that I have received contained the following:

  • 1 x Coil Master 521 Tab
  • 1 x Snap-on adaptor for voltage readings
  • 1 x micro USB charging cable
  • 2 x alligator test leads
  • 1 x user manual
  • 1 x promotional giveaway leaflet

Coil Master 521 Tab

Look and feel

The first thing that caught my attention was it’s design, it’s a beautiful device with a small form factor. The size of the device is spot on for it’s purpose, it’s not too small to make it difficult to build on or too big to leave it at home. The device is 84.5mm long X 69.5mm wide x 49.5mm in depth. Size wise it is comparable to an ohm meter but slightly bigger. The overall material used is hard plastic (ABS) for the device and the shape is ‘box style’.

On the top of you device you will have your building deck with the integrated 510 connection, which looks recessed into the aluminium top cap, the 510 brass pin is spring loaded and it has made a connection with all the atomizers I have tested. The device also features an LED display on top of the 521 tab, the display is nice an bright and shows the necessary information (ohms/voltage). The previous version of the 521 tab featured an OLED display that also showed a battery meter and had a couple of graphics when you were in firing mode, the version I have on review is the newer model that doesn’t have the OLED display.

Coil Master 521 TabI favor the old OLED display but there is merit in keeping things simple (for instance it saves battery life). Next to the display you will find a big firing button that sits nice and firm and has a pleasant sound to it. On the left part of the display you also have a blue LED to let you know that you are in firing mode. On the right side of the device you have your mode selector (burn/off/reader) and down below you have your micro USB port for charging. Coil Master 521 Tab

The left side of the device has Coil Master 521 embossed that adds to the design and details put into the device. On the bottom side you have the battery compartment that is fixed into place with two tabs to prevent the cover from sliding off and magnets to prevent it from falling and to allow you to easily replace your 18650 battery without tools. The battery cover also has 4 rubber pads to prevent the 521 tab from moving on your table or any surface when you are doing your builds.

Coil Master 521 TabGoing back on top of the device the 510 base also has 2 ports for adding your voltmeter adapter (included) or attaching your alligator test leads. When the device is in reader mode you also have another great feature which is the led ring around the 510 base that lights up in red, again this is another nice addition in terms of features and design.

Quick Specs:

  • Dimensions : 49.5mm x 84.5mm x 69.5mm
  • Weight: 190g
  • Housing material: Plastic ABS
  • Resistance Measuring Range: 0.01 – 9.99 Ohms
  • Voltage Measuring Range: 0.3 – 9.99 Volts
  • Resistance rate (firing capability): As low as 0.2 ohms
  • Connection : 510 threaded with spring loaded pin
  • Charging: 4.5V/ 750mah Micro-USB Charging input
  • Battery: one 18650, 3.7V (Battery is not included)
  • Reverse battery protection

Building on the Coil Master 521 Tab

After some extended use I can report back to you that for me personally it has been a pleasure to build on this device. The device has the perfect height and it feels almost natural to build on it, there is nothing that is out of place or stands between you and your build. And the fact that the device allows you to fire your coils directly on it is a huge plus. Everything you need can be done with ease in one place, you can read your coil resistance and fire your build to preheat the coils and ensure there are no hot spots. With this feature Coil Master has managed to eliminate the need for us to take the atomizer away, screw it on our mod and test fire it.

Resistance Testing of your coil/wire without a build deck 

The Coil Master 521 Tab will allow you to test and fire your coil/wire without even placing it on a build deck, the included alligator clips will enable you to do just that with ease and no trouble. This is particularly useful when you have finished your coil and want to test it out prior to screwing this on your atomizers deck if you are uncertain of the actual resistance.

Checking your voltage on a mechanical or regulated mod

Coil Master 521 Tab

To check the voltage on your mod all you need to do is to add the voltage snap-on adapter on the top of the Coil Master tab and screw your regulated/unregulated mod on it. The device will then display the actual voltage drawn when the mod is fired.



Vape using your Coil Master 

Coil Master 521 TabAnother great feature for this device is the fact that you can use it as an actual mod, you can vape on it 🙂 Screw you atomizer on the Coil Master Tab, push the mode selector into burn mode and press the fire button and that’s it, you have a mod replacement tool too in case something has gone wrong with your mod or you have lost yours. This is a nice back-up solution when you have nothing to vape on until your replacement mod arrives.

Overall impression

Coil Master 521 TabAs I mentioned during the course of this review, in all honesty I think this is a great device to have, the fact that it is a multi-purpose tool (voltage meter/ohm reader/mod) in such a small form factor it makes it the perfect go to solution for everyone interested in doing builds. During my time with this device I have certainly enjoyed using it and it has made everything for me much easier when I am doing my builds. This is a perfect tool for both the experienced and new vapers out there, for experienced vapers it just enables you focus on your build as a hassle free experience and for the new vapers out there this will help you build your coils easy and safe.

Regarding pricing, the Coil Master 521 Tab now costs 39.99$ and you can purchase it directly from Is it worth 39.99$? In all honesty I think it does, it will certainly not break your vaping budget and it does offer a lot of useful features for a good price point. If you don’t believe me try one out if a friend or vape shop has it and let me know what you think.

If you have enjoyed this review, please remember to like, comment and share, thanks 🙂Coil Master 521 Tab  Coil Master 521 Tab

Coil Master 521 Tab