This New Metal Chamber Set have three functions in one:
1.The LED Tracer Unit (INCLUDED)
2.Chamber Lock (Is design by Brian Holt)
3.Easy Adjustment Wheel device
Metal Hop Up Chamber Unit Set
LED Module can change your Hopup chamber to be a tracer unit

Features:
Voltage: 7.5-12.6v
Life 10000+ hrs
1 Watt
8 Blue SMD LED (O.C.)

No silencer type tracer unit anymore, shot illuminated BB without losing balance of weapon
Suitable for M4 / M16 Series Airsoft Electric Rifle AEG

Note: Once pluged with battery, LED module will start consume battery (1 watt.) You have to unplug the battery to turn it off.