Kinetic Wares Manufactures Glass Reinforced Nylon and Polycarbonate O-Ring picks. Trying to decide which is best for your application. The Polycarbonate Picks are more pliable making them perfect for softer plastic parts such as water filter housings, or bypass valves. Glass Reinforced Nylon has less flex and is stronger for use in automotive, air or hydraulic fittings. They will take a little more abuse.