Item No PN-EXT98802LPFSCS SPEED PASSION GT V2.1 "EX" Brushless ESC - Competition Silver GT2.1 EX series ideally designed for 1/12th scale applications and 1/10th WGT racing. It feature the all new "Auto-detect" power input (auto select how many number of cells) without choosing the power input manually. And there are no need of using any voltage booster or external receiver battery pack even using the single cell lipo battery. It has the ultra-low profile heat sink design that flushed with the case and it will fit all the 12th scale bodies and 10th scale WGT bodies without any rubbing problem. It is also a perfect fit for 2WD off road buggy which need to be very low in height in order to fit their body.