This is the Spektrum SR410 4-Channel DSMR Sport Surface Receiver. Bashers, boaters, rock crawlers, racers - the SR410 receiver is ideal for anyone wanting a sport receiver that can handle the worst nature and the RF environment can throw at it. It's built around frequency-agile, DSMR technology that delivers superb range and response, especially in places where a lot of 2.4GHz systems are in use at once. This unbeatable signal security is complemented by a fuel-proof case and Reliakote™ conformal coating that seals internal electronics from the elements and other corrosives like nitro methane or motor spray.

Features:

Specifications: 
Type: 2.4GHz 4-channel DSMR Sport Surface Receiver 
# of Channels: 4 
Modulation: DSMR 
Band: 2.4GHz 
Length: 1.29in (32.8mm) 
Width: 0.80in (20.3mm) 
Height: 0.53in (13.5mm) 
Weight: 0.25oz (7.2g) 
Voltage Range: 3.5-9.6V 
Antenna Length: 210mm Coax Antenna