40A Brushless 2 4S ESC Speed ​​Controller with BEC 5V 3A for

1 Piece 2-4s brushless ESC. Timing can be changed to be suitable for different brushless motors. BEC output: 5V@3A (linear regulator mode - linear mode). Maximum speed: 210,000 rpm for 2-pole motor, 7000 rpm for 6-pole motor, 35,000 rpm for 12-pole motor.

eBay