Paul is a chemical engineer working in a coating division of a large semiconductor fabrication facility. He is tasked to order a large set of O-rings for vacuum valves in chemical vapor deposition, sputtering, and metal evaporation systems. A large selection of O-rings from different elastomers is available. These O-rings vary in price and have different operation temperatures, as shown in the table below: O-Ring Price Table Elastomer Price (per 10) Operation Temperature (F) Buna-N $120 -35 to 250 Kalrez $180 -15 to 620 Polyurethane $100 -30 to 180 Silicone $140 -65 to 300 Viton $160 -15 to 437