These are the new BLHeli_S capable ESC from DYS.  These ES utilize the new high-performance EFM8BB2 50MHz MCU, capable of handling up to 500k eRPM and able to support motors with super high Kv.  The hardware generated PWM signal gives makes the motor perfectly synchronous to the MCU, resulting in ultra-quiet and ultra-responsive motor performance.   For details on what is BLHeli_S and how it is better, check out this great article from the DroneTest bog Key Features: Silabs EFM8BB2 50MHz MCU  Weight: 8.65g  Support input voltage from 3S to 6S  Size(mm)L*W: 45mm*16.5mm*8.5mm  BLHeli_S does Damped Light only  Firmware upgradable via signal wire (works with USB Linker for XM series)  Supports 1-2ms signal, Oneshot125, Oneshot42 and Multishot.  High-current burst rating  High-Resolution Throttle steps