Youde UDT V10 Mechanical Mod -18350SALE by Youde $55.95 $59.99
Additional features such as adjustable floating pin which you can flash mount any 510 thread tanks, and top cap has been cut with 3 channels for airflow.
Turn clockwise to unlock button, and anti clockwise to lock button.
From Youde's test result, this mechanical has almost no voltage drop.
Size: Dia 25mm, H 74mm
Battery size: 18350 only