Check the listing for details. SolarPoolSupply End Cap for Solar Pool Heater Panels (Reinforced Polypropylene). Condition: New. Listed at 10.80 USD. Manufactured from glass-reinforced polypropylene, providing increased strength, stiffness, surface hardness, and higher continuous temperature protection reducing distortion under long-term stress. Compatibility: Will work with any solar pool heating system that has round 1.5” or 2" I.D. header manifolds and makes attachments with rubber hose type connectors. Measurements & Sizing 1.9″ (1-7/8″) O.D. End Cap: For solar pool panels with 1-1/2″ headers (1.5″ manifold I.D. / 1.9″ O.D.) Fits rubber coupling hoses with 1.9″ (1-7/8″) I.D. 2.375″ (2-3/8″) O.D. End Cap: For solar pool panels with 2″ headers (2″ manifold I.D. / 2.375″ O.D.) Fits rubber coupling hoses with 2.375″ (2-3/8″) I.D. Product Data Manufacturer: Solar Pool Supply MPN: 30061 30061-1 (1.5" I.D. Header) 30061-2 (2" I.D. Header)