R404SBS-E SR/T-FHSS/S.Bus2 Telemetry Receiver (Indoor Optimized) High Speed Response System for EP Car Models SR Mode servos must be used when using SR mode. Use of normal servos may cause servo issues. Not for use in GP (Gas or Nitro) powered cars.

Specs:
Dimensions: 25.5x20.7x10.6mm (1x.81x.42in)
Weight: 5.7g (0.2oz)
Operating Voltage: DC 3.7V-7.4V