This is the Futaba R204GF-E-S-FHSS 2.4GHz Four Channel HV Micro Receiver.

FEATURES: Ideally sized for 1/10 and 1/12 scale vehicles including rock
crawlers
Compatible with any Futaba S-FHSS/FHSS system
S-FHSS mode offers two operation modes: Normal and High Speed
responses
Internal antenna
One year limited warranty through Hobby Services beginning at date
of purchase

INCLUDES: R204GF-E-S-FHSS 2.4GHz Four Channel HV Micro Receiver

SPECS:    Operating Voltage: 4.8 - 7.4V
Receiving Range: 230' (70m)
Battery Failsafe: 3.8V
Current Drain: 30Ma (at no signal)
Size: 1.38 x 0.91 x 0.35" (35.1 x 23.2 x 9mm)
Weight: 0.21oz (6g)