MRT Transponder for AMBrc/RC4 (v4.4) | Stormer Hobbies

Overview

The MRT Transponder from MRT is designed for AMBrc and RC4 timing systems, offering a lightweight, compact solution that fits neatly into tight spaces inside your RC car. Stormer Hobbies uses these transponders personally, so you can trust their reliability across practice sessions and league events.

With a 100% waterproof construction and a weight of just 4 grams, this transponder disappears inside chassis and bodywork while maintaining solid performance under race-day conditions. Its footprint measures 19 x 16 x 6 mm, ensuring it stays out of the way during maintenance and setup.

Key specifications

• Size: 19 x 16 x 6 mm
• Weight: 4 g
• Lead length: about 190 mm from Stormer Hobbies
• Operating voltage: 2.1 V - 16 V DC
• Mounting: Standard 3-Hole (same as AMB/MyLaps)
• PTX transponders ship with two stored IDs and come factory set on the custom ID with an alternative number available
• LED indicator shows the transponder status during operation

For user setup, the LED lights up when the transponder is powered. When you set or verify the ID, the LED flashes to indicate the selected number, giving clear on-board feedback.

System compatibility

The MRT Transponder works with AMBrc2, AMBrc3, and RC4 systems up to version 4.4. It will not operate with the v4.5 Drone System update.

Real-world use cases

• Fits into small, cramped areas in many RC models from brands like Associated, Xray, Losi, CRC, and Serpent
• Two stored IDs let you run multiple setups without swapping hardware; switch IDs as needed for different events or cars
• LED feedback provides quick, reliable checks that the unit is powered and the selected ID is active

Racers and hobbyists around the world rely on MRT transponders for consistent timing on AMBrc/RC4 systems, especially when space is limited or you’re outfitting a mixed fleet of cars. The 190 mm lead keeps the transponder accessible without stressing connectors, while the waterproof design helps on wet tracks or splashy pit days.

Why choose MRT transponders?

• Proven compatibility with a broad range of RC cars and timing systems
• Small, lightweight form minimizes aerodynamic and weight impact
• Two IDs provide flexibility across different setups
• Clear LED status supports simple setup and on-track checks