Pulley Large Demonstration Single, Designed for Classroom Demonstrations, Light-weight, low-friction, and deformation-resistant plastic ensures accurate results, Open to make it easier for users to run pulley cords through them
Y-Shaped Flint Glass Connecting Tube, Arm Length: 1 1/2in, with a 120 deg angle provides safer connections as the ends have constrictions to hold rubber tubing securely, Made from quality flint glass, Size: 1/4in ID X 5/16in OD (7.9mm)