Materials: Made of high quality material.Sturdy and durable. Intention of the modification: Modification, different spring elasticity requirements Feature: There are red (medium strength) ,blue (light strength) and yellow(soft).*Red(TM) is slightly harder; *Blue(TL) is obviously softer.(but maybe harder than original); *Yellow(TS) is the softest Suitable for: THRUSTMASTER T-LCM Pedal Packing includes: 3 x Spring