See all products of Mechanical O-ring seal for solar thermal systems Female fitting, mechanical O-Ring seal for solar thermal systems. Coupling sleeve, mechanical O-Ring seal for solar thermal systems. Male fitting, mechanical O-Ring seal for solar thermal systems. Elbow coupling sleeve, mechanical O-Ring seal for solar thermal systems. Elbow coupling sleeve, mechanical O-Ring seal for solar thermal systems. Male elbow fitting, mechanical O-Ring seal for solar thermal systems. Female elbow fitting, mechanical O-Ring seal for solar thermal systems. Plug for Ø 22 copper pipe.