John Guest Acetal Copolymer Tube Fitting, End Stop, 1/4" Tube OD (Pack of 10) End stop for closing the end of a pipe or fitting Accepts nylon and polyurethane tube fittings Made of acetal copolymer plastic for low moisture absorption and high tensile and flexural strength Working pressure of up to 150 psi Meets NSF/ANSI standards 14, 51, and 61 for quality assurance