This is the Traxxas 2.4GHz Micro 4-Channel Receiver.
Features: 2.4GHz For use with the Traxxas TQ 2.4GHz 4-ch Spread Spectrum radio
Includes: One 2.4GHz 4 Channel Micro Receiver
Requires: Installation in vehicle and connecting battery and servos
Length: 38mm (1.5")
Width: 26mm (1")
Height: 16mm (0.63")