This is the Hobbywing XRotor 20A Micro Brushless Drone ESC.

Features:

Super Small & Light architecture
F396 48MHz MCU
Premium MOSFETs (Toshiba MOSFETs for 20A & 35A ESCs, Fairchild MOSFETs for 30A ESCs)
Ceramic capacitors
3-in-1 drive ICs, 3-ounce copper
Ultra high efficiency & rapid response – 4 layers of PCBs and other quality components guarantees less heat.
BLHeli Firmware Ready – Users can flash or upgrade the BLHeli firmware via the signal cable (on ESCs), and program 4 ESCs simultaneously after connecting their flight controller to the BLHeliSuite software if the flight controller uses the CleanFlight firmware
Damped Light Mode & OneShot125 Mode Supported
Damped light mode improves the motor retardation and allows users to brake the FPV drones more efficiently. Active-freewheeling technology improves driving efficiency, flight time and heat dissipation.
Support OneShot125 high speed throttle signal and regular throttle signal (within 500Hz) modes.
ESC + Motor combo available

Specifications:
Application: FPVs with 130-280mm Diagonal
LiPo Power input: 2S-4S
Continuous Current: 20A
Burst Current: 30A
BEC Output: NA
Input wires: 20AWG-100mm* (Red/Black)
Output Wire: Solder tabs (no wires)
Connectors (In/Out): no
Weight / Size: 7g / 24.0×13.9×5.5mm
*Note: All the wire length above is the original length, not the length you see from the outside.