This is the MYLAPS RC4 "3-Wire" Direct Powered Personal Transponder. In R/C racing, details matter. The slightest change or modification can be the difference between making the box, or being a back marker. So MYLAPS developed the next generation RC4 3-Wire transponder to do more than just count your laps. The RC4 3-Wire provides the user with telemetry data such as lap times, connected voltage and ambient car temperature, information that can be used to shave seconds off your overall times. RC4 transponders are compatible with RC4 timing systems can be used for both indoor and outdoor on-road and off-road racing and will perform on just about any surface. 

Specifications: 
Max Speed: 120 km/h (75 mph) 
Temperature Range: 0 - 50°C (32 - 122°F) 
Dimensions: 16x19x6mm (0.7x0.8x0.2") 
Weight (Including Holder): 4.7g 
Operating Voltage: 3.0 - 16 VDC 
Humidity: Max. 90% relative 
Signal Transfer: Magnetic induction 
Code Resolution: 1.5 ms 
Power: Feed from free receiver channel (ch3 or batt) 
Connection Plug: Connect using a standard Servo plug 
Power Consumption: 14mA @ 6 VDC 
Wire Insulation: Aerospace/MIL-spec high-temp PTFE (Gasoline/Nitro resistant) 
Quick Change Holder: Yes 
Compatible With: RC4 Timing System only!