There are quite a few options seen for 18650 powered mods. The Luxyoun UNIX is a nice looking wooded box and comes in 30w as well as(correction made) 50w, 100w and the 150w model used here that came out a couple of years back taking a single 18650 and is upgradable as well as seeing the battery charged by usb to micro usb. Ordered back then from a vendor in Hong Kong as the only place seeing the V1 until looking now for the same.
Luxyoun Unik (30W, 50W, 100W, 150W) – $54.66 – $66.91
The wooden mods are very light weight and this is not bulky but trimline for a wooden box mod. The edge of the display on the one I have here however sticks out just a hair on the left side while the rest of that is recessed into the opening for that. Still trying to figure out how to get that to sit down without damaging the box or opening while may have to file the opening in case of a bur causing it to lift up a bit. The mod has been reliable but will kill off batteries when left unused too long since the display is a constant draw on the battery itself while small.
The UNIK V2 is now available with the Bing photos you can look over seen at:
luxyoun unik v2 - Bing images
The iStick 40 with temp control and 50w non tc are sealed batteries that seem to last longer then anything else as for battery time with the 50w model.
Having push to hold in longer then others type problems with the ICIG V9 50w mod otherwise another single battery 18650 box mod.
icig v9 50 watt - Bing images
(Flaky fire button downfall there while the rest of the unit seems to be a durable product!
Presently examining a 100w iStick that runs on two 18650s with the high drain 3100mah Panasonics in use while having a new Freemax Scylla premade/RDA type tank where you can stick with the premade or wrap your own with the separate RDA platform you fasten in. I paid $34 and turn around and find it at another vendor I screen and only $26!
iStick 100W Box Mod by Eleaf $25.99
Taller however like the MVP 3.0 Pro.
Innokin's CoolFire V 70TC is a thought but another sealed 3300mah battery as well as a new one seen on the Alababa site or 3FVape being the VAPMOD XTube 60w sealed only the 8ml tank is inside! That's on the idea of the eGrip but sees twice the wattage over the eGrip's 30w and a larger tank which runs with sub ohm coils. Unfamilar brand however.
Authentic Vapmod Xtube One 60W Golden 2500mAh TC Mod Kit
(Just found a buy on the Cool Fire IV Plus for $25-$40 less at a domestic US vendor 70w 3300mah sealed battery which actually are not so bad and seem to supply a slight increase in amps when swapping the same tank between mods with 18650 batteries in use like the Clouper ZNA 50 or 50w SMOK BEC Pro.
Innokin CoolFire IV Plus - EXPRESS )
Not really into the TC here and was looking at the price for that but just saw the iStick 100w TC only after ordering the first 100w model that hasn't been out long for less before seeing that one. But it will depend on wattage as well as the price.
I still run the Dovpo E-LVT 30w "Indestructable Mod" sub ohm capable all vinyl mod you can drop and not worry about that takes a single 18650 in that as well as charged by usb. That requires the phillip head to replace the battery as many do. But a bit heaver in weight despite the compact size being the drawback!
The new iStick 60wTC taking a single not double like the 100w model on the other hand sees a pair of magnets on the battery cover and no springs on the battery contacts. You have to line the battery up at both ends and press down in place.
iStick 60W TC $28.99 - $34.95 Temperature Control by Eleaf
I almost went with that but already have too much in the 50-60w range between 3 50w iSticks, 2 40wTC iSticks, the original pair of 20w and a 10w tossed in a case. Plus the 60w MVP 3.0 Pro another one a bit taller and just a little bit more weight over the 50w iSticks. The ZNA 50 I got back in 2014 will feel like bar stock in your hands with two 18500 and 18650 battery tubes recommending a high drain type for that while that certainly would be out there for sure while the Aspire Odyssey is a 50wTC that takes a single 18650 as well. I use Aspire tanks but so far still haven't tried one of their mods out however.
Aspire Odyssey Mini Full Kit
Does size matter as it sounds like the size of the 50w iStick would be about right and the sealed battery isn't junk nor are the buttons! The buttons on the 100w just in are stainless for that and rigid. The 50w here sees a belt holder added on that with a 510 extension to allow room for the washer that comes with the belt clip type holder you can slip into a pocket while the clip part is on the outside to prevent it falling!
Amazon.com: Eclyp Omni HD (Heavy Duty) Pocket Clip for Tube or Box Mod **Not an e-cigarette**: Health & Personal Care
Another i18650 powered Kooper Mini 60w with Temp Control can be looked over but no direct information can be seen at
Koopor Mini 60W Temperature Control
If you are looking for something more specific as far as wattage range the mods posted here are in varying power ranges. While most mods will be found to be delicate to start with the iStick 50w and lately the 40w TC models have proven themselves to be durable goods for the sealed battery type. If you decided on any of these you can pm me for a best price since I price shop everything as well as screen vendors in general. I keep a list of Approved vendors only for recommendations on the social networks as well as including vendors listed here at ECF as well.
