R304SB-E– T-FHSS Telemetry System 4-Channel Receiver (Indoor Optimized for smaller carpet track type cars where space is at a premium!) For EP Car Models (01102180-3) T-FHSS SIZE:35.1 mm x 23.2 mm x 12.5 mm WEIGHT:7.0 g RATED VOLTAGE:DC 4.8V-7.4V OPERATING VOLTAGE:DC 4.0V-8.4V NEVER USE THE R304SB-E IN GP CARS USE OF ANALOG SERVOS MAY CAUSE SERVO TROUBLE

Futaba R334SBS-E T-FHSS SR S.Bus2 4-Channel 2.4GHz Receiver.   NOTE: Not compatible with the Futaba FHSS, S-FHSS, FASSTest or FASST transmitters. Features: Surface 4ch 2.4GHz T-FHSS SR Diversity 2.4GHz T-FHSS S.BUS2 Frequency 2.4GHz Surface Use 4 Channel  Specifications: Input Voltage 4.8-7.4 V Weight 7.2g Dimensions 33.9 x 22.3 x 11.3 mm

Specifications: Dimensions 1.00×0.81×0.42 Inch 25.5×20.7×10.6 mm Weight 5.7 g0.2 oz Operating Voltage DC 3.7V-7.4V SR Mode Servos must be used when using SR Mode. Use of normal servos may cause servo trouble. Never use the R404SBS-E in GP Cars.