"Carb-O's" are silicone throttle return bands from GMK Supply. These small silicone bands are super stretchy and work awesome as throttle return springs for all nitro engines from .12 to .32 in size. Double them up if you need more strength, or wrap them multiple times. These bands stretch!

“Carb-O’s” help prevent runaways, and comply with racing rules requiring throttle return springs. These bands pull evenly on the carb slide, preventing binding of the slide that can occur with a coiled metal spring.