This is an R156F 6-Channel 72MHz FM Receiver "Without Crystal" from Futaba. It is NOT suggested to go below channel 16 with these receivers as you may experience interference. FEATURES:  Narrow-band spacing and superior signal filtering combine to provide exceptionally clear, interference-free reception and amazingly smooth, accurate control Perfect for Park or Slow Flyers Range of approximately 500 feet (167m) Uses standard size servo connectors This covers the complete 72MHz band One year warranty INCLUDES:  One R156F 6-Channel 72MHz FM Receiver without Short Crystal REQUIRES:  One FUTL63** "Short" Crystal (High) FUTL62** "Short" Crystal (Low) If utilizing all 6 channels a Y-harness is needed, HCAM2500. SPECS:     Narrow Band: 20kHz Power Requirements: 4.8 to 6.0V (shared with servos) Current Drain: 10mA Length: 1.3"  (33.3mm) Width:  0.51"   (13mm) Height: 0.84" (21.4mm) Weight: 0.36oz (10.2g)