Patented Special Reinforced (SR) Thread Design Spears® patented Special Reinforced (SR) thread design is one of the most significant advancements in the use of plastic threaded fittings. More than just an added metal ring, this unique precompression design compensates for expansion forces generated from tapered pipe thread joint make-up. Radial stress is reduced in normal installations and contained in severe over tightening situations. SR style fittings use type 316 Stainless Steel reinforcement. Full 150 psi Pressure Rating For Threaded Systems Using SR Threaded Fittings Spears® SR threaded Schedule 80 Polypropylene fittings provide the reinforcement necessary to provide threaded systems with full 150 psi pressure rating for water @ 73°F, typically found only in fusion welded systems. High Grade Homopolymer Compound - Excellent Chemical Resistance Spears® selection of a premium polypropylene homopolymer provides improved purity with excellent chemical resistance to many solvents, caustic solutions and mixed chemicals for a wide variety of applications. Available in natural or black materials. (For black, please call 818-340-7258 for pricing)