This is the HPI RF-30 2-Channel 2.4GHz Receiver. FEATURES: Exclusively for the HPI 2.4GHz TF-20U radio (not compatible with the TF-40) Fail safe system if radio signal is lost Low voltage cutoff INCLUDES: HPI RF-30 2-Channel 2.4GHz Receiver with Instruction Sheet REQUIRES: 6V 5-cell receiver battery SPECS: Length: 1.02" (26mm) Width: 0.90" (23mm) Height: 0.51" (13mm) Weight: 0.26oz (7.5g) COMMENTS: Not recommended for cars with ESCs or 4 cell receiver packs jxs 07/26/11 ir/jxs