This is a front heavy duty Gas Shock absorber for the Triumph TR4A, TR250 and TR6. Get rid of the mushy feeling shocks and upgrade to a gas shock absorber. The advantages of the gas charged shock absorber is the pressure in the shock keeps the dampening oil from foaming. Foaming in not good in a shock absorber because it looses it's ability to dampen the ride because air bubbles are created. With these shocks your car will handle better and be a pleasure to drive.