Wismec, which is actually owned by Joyetech, have a nice little 40 watt device called the Wismec Presa. This device is quite tiny as it’s about the size of an iStick 30w or 40w. What’s nice about the Presa is pretty much the entire front of the device is the fire button which makes firing it very comfortable regardless of how you hold it. Inside it has a built in 2600mah battery with a micro USB port for charging. It can be used in wattage mode or voltage mode with a range of 5 watts to 40 watts and 2 volts to 10 volts. For those that like to sub ohm, the Wismec Presa will fire down to 0.2ohms. Also, it has a spring loaded 510 pin.

Details:

Security lock, comfortable and functional
Thermal protection function
OLED display that shows remaining battery charge, ohms of resistance, voltage and power work in watts
Micro-USB port charging: Allows you charge the battery while you use (passthrough mode)
Port 510 mounted flush with the casing so that your atomizers fit perfectly
Self-adjusting floating pole
Stainless steel screw
Variable wattage from 5W to 40W 0.1W increments
Variable voltage from 2V to 10V in 0.1V increments
Battery Capacity: 2600mAh
510 with self-adjusting threaded pin
Range Resistance: 0.2ohm-5.0ohm
Length: 81.9mm
Width: 34.9mm
Thickness: 24.4mm