Receiver Booster MetalGarage Receiver Capacitor Receiver Light Blue LED Insert into an empty port of the receiver. Lights up in light blue. Improves machine controllability. Using it together with the separately sold Propo Capacitor makes the machine even more controllable. Recommended for beginners to experts. Employs a high polymer capacitor, and despite its compact size, it has 6 times the capacity of conventional capacitors, and a lifespan of 20,000 hours, which is 10 times longer than the 2000 hours of general capacitors. The cars equipped with this product took all three podium positions at the GRK qualifying event.