This is an AMB-compatible transponder. It can be used for 1/12 to 1/10 scale R/C cars. Please connect it to a free channel on your receiver. Size: 19 x 19 x 6mm Weight: 4g Cord Length: 130mm (excluding connector) Operating Voltage: DC 3-16V Current Consumption: 14mA@6V Reverse polarity protection circuit Dust-proof specification to prevent dust from entering, which can cause transponder failure. Recommended transponder mounting positions by the manufacturer: o Do not mount directly on a carbon chassis. o Do not mount more than 15cm above the road surface. o Do not mount near heat-generating parts such as the motor. o Use vibration-damping tape if there is vibration. Compatible AMB decoders (can be used on courses that support other companies' AMB-compatible transponders): My Laps RC2 My Laps RC3 My Laps RC4 (up to decoder firmware 4.4) This is a used item. It was working without any problems until it was removed. Thank you.