50 pcs Plastic O-Rings 1 Inch (25 mm) 50 pieces per pack. Free shipping. Work with 1 Inch (25 mm) webbing, strap. Breaking Strength 99 lbs, 45 kgs. Breaking Strength can be varied with respect to individual applications. These figures are offered as reference only and are not to be used as guaranteed performance figures. Products should be tested in their specific application. Made of Polyoxymethylene (POM), also known as acetal, polyacetal, and polyformaldehyde, is an engineering thermoplastic used in precision parts that require high stiffness, low friction and excellent dimensional stability.