This is the Futaba R204GF-E High Voltage 2.4GHz S-FHSS 4-Channel 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

Specifications:
Operating Voltage: 4.8 - 7.4V
Receiving Range: 230' (70m)
Battery Failsafe: 3.8V
Current Drain: 30Ma (at no signal)
Size: 1.38x0.91x0.35" (35.1x23.2x9mm)
Weight: 0.21oz (6g)