Ystar Kerui RDTA review | A new and unusual RDTA

The Keuri from Ystar is an RDTA and RDA convertible device.

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Ystar Kerui RDTA intro

Ystar has just released the Kerui RDTA, a new “convertible” which doubles as an RDA. In the RDTA configuration the Kerui features a unique top tank design which allows you to drip juice on demand to the deck. When your coils get dry, twist the tank to open the dual ports on the bottom of the tank and juice drips onto the deck below.

The deck features a spring-loaded clamping system which will accept exotic large diameter wire. When you loosen the knurled deck screws the clamps pop up under spring pressure to accept the coil wires.

The top-fill Kerui is 25mm in diameter and features top and bottom airflow, which can be used separately or concurrently by adjusting the AFC ring. Capacity is not given, but I measured approximately 2.5ml with a syringe. The Kerui comes with two top caps: one with an Ultem drip tip and one stainless steel – the tips cannot be removed.

The RDTA is held together by o-ring friction between the various parts and quickly converts to an RDA by removing the tank section. The Kerui made from 304 stainless steel in your choice of three finishes: black, gold, and of course brushed stainless steel.

Ystar Kerui RDTA Specs and Features

Kit Content

  • Kerui RDTA
  • Top cap w/Ultem tip
  • Top cap w/SS tip
  • Screwdriver
  • Spare glass
  • Spare o-rings
  • Spare deck screws

Specifications

  • Diameter: 25mm
  • Height RDTA: 52.5mm
  • Height RDA: 33mm
  • Capacity: 2.5ml (unofficial)
  • Material: 304 SS and Ultem (PEI)

Notable Remarks

The Keuri RDTA first impression

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(Kerui name: Deeply independent, vivacious, quick and enterprising by nature.)

With good heft, finish and the Ultem tip the Kerui makes a great first impression out of the box. Admittedly, I was a bit confounded by the top tank design and grabbed the instructions to help wrap my brain around its function. The instructions are a bit lacking so I decided to just experiment.

Under the hood

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The Kerui is comprised of seven separate parts all held together by o-ring friction. Other than the deck screws and 510 connector, the entire RDTA assembly has not a single thread. This may alarm folks worried about the tank inadvertently coming apart in their pocket or pack. I did lift my mod by the tank and it held, but carry the Kerui at your own risk.

The deck is a breeze to build and is a lot like the Hadaly by Psyclone Mods with the clamps located on opposing sides of the deck, and a single screw securing each clamp. Loosen the knurled screws the two clamps pop up under spring tension, which is a nice touch and makes it simple to insert your coils leads underneath. Careful though: if you loosen the screws too far they can pop out and you may lose the tiny springs, and no spares are provided. The deck can still be used but the springs make it much easier.

Moving up from the deck, the chamber features two generous air slots on the bottom and two on top, which you can adjust to work in tandem or separately.

If using the Kerui as an RDA, the final piece is the top cap. In the RDTA mode, the tank attaches between the deck/chamber and the top cap. On the underside of the tank are two ports which allow juice to drip onto the deck. When it’s time to drip, hold the base of the Kerui with one hand, grab the top cap/tank with the other and turn the top portion clockwise until you see bubbles rise in the tank. When you are done, turn it back to close the juice ports and vape. The chamber is keyed to the deck to prevent movement when you are turning the upper portion to drip.

Performance of the Keuri

I tried the Kerui as an RDA first. The spring loaded clamps made it simple to build. I installed a single fused clapton that came in at 0.9Ω. The knurled clamp screws are a nice touch, but I used a screwdriver to secure the clamps.

At 40W with the bottom air wide open and the top closed the RDA performed well, and gave me nice vapor and flavor. At higher wattage it got a bit hot on the lips so I opened the top air and it cooled a bit. As expected the flavor also dropped off – not bad but noticeable.

OK, onto the RDTA.

I removed the top cap and installed the tank. Making sure I had the juice ports closed, I filled the tank with Cuttwood Mr. Fritter at 70% VG. The coils were already primed from use as an RDA, so I vaped until the coils were getting dry. Now the moment of truth: how does the drip function perform?

I opened the juice ports and juice literally poured into the deck and out of the bottom air slots. OK, there is obviously a learning curve. I cleaned up the mess and refilled. The next time I needed to drip, I SLOWLY opened the juice ports and watched for bubbles in the tank and then closed the ports. Trouble is, you have no idea if you have enough (or too little) juice until you vape. It is total guesswork, and if you are wrong, you get a dry hit or juice leaking out of the bottom air slots.

Once I finally got the Kerui squared away it vaped pretty well. I was able to vape it at higher wattage since the coil was further away from the drip tip with the tank and chimney installed.

Likes

  • Clean design
  • Good finish
  • Nice weight
  • Ultem drip tip
  • Clamp system
  • Easy to build
  • Good RDA performance
  • Good vapor and flavor

Dislikes

  • Unnecessarily complex
  • Easy to over drip and leak
  • Friction fit components
  • No mark to align deck with chamber
  • No spare clamp springs
  • Poor user manual

Verdict

I like easy, and the Kerui is not.

While it is simple and straightforward as an RDA, the RDTA is unnecessarily complex to use. Besides the fact that the entire assembly is held together with o-rings, it is literally impossible to regulate or even see that state of the wicks. There is no easy way to remove the top to check without the entire assembly coming apart and creating a huge mess.

The only way to semi-safe way to remove the tank without a mess is to remove the RDTA from your mod and hold it upside down while pulling off the deck, all the while hoping the tank doesn’t pull apart. And while I understand that the keyway is necessary to keep the chamber from turning, it is a real PITA to line up especially when your hands are covered with the juice pouring out of the tank.

While I applaud Ystar for attempting something different, the execution just lends itself to a poor experience for the user. If the Kerui were threaded together I would like it a lot more, but there is still the juice flow control (lack of) to contend with.

There are just too many better options competing for my hard earned dollar for me to want to fuss with the quirky Kerui.

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Gary Joseph
Gary is a retired technical writer residing in the metro Detroit area. Besides vaping, and writing for Vaping360, some of his other interests include motorcycling, watch collecting, bicycling and fitness.