... the Shocker was not invented by Smart Parts, it was invented by pneusventure (PVI). They made things for Nasa and were experts airsmiths, thats why the original Shocker only had one spring, which was to close the valve. And SP was just the "production company" for the marker. Later on SP ended the production contract with PVI and they sold the Shocker as there own, when it was not. This ended up putting PVI out of business after they tried to re-release the Shocker under different names including the Warrior. SP ended up buying all the rights but one to the Shocker, which in 2004 WDP found out about from one of the original inventors of the PVI Shocker and bought to stop SP's reign of law suits. There is a site on just the PVI Shocker alone too so you can learn things about it from there. But I just wanted to clarify this for you because many people thought SP invented the Shocker when they did not.