This is the Futaba R608FS 2.4GHz FASST 8-Channel Park Flyer to Giant Scale Aircraft Receiver.

Features:
A full range system for all aircraft from giant scale to Park Flyer applications-no need to buy separate receiver for
specific aircraft
Simple one-touch binding - no plugs to mess with or lose
Dual Antenna Diversity allows 2.4GHz FASST Futaba transmitter to select the best reception between the two receiver antennas with signal loss
Rubber grommets installed where antennas exit to eliminate stress
and fraying of the two antenna wire

Specifications:
Size: 1.8 x .9 x .5" (45 x 22 x 12.7mm)
Power Requirement: 4.8 - 6V