Erickson's adjustable tarp straps have heavy reinforced holes every 6" along the strap to hook back into, or move the end hook to make shorter.E.P.D.M. rubber has average strength and is very resistant to ozone and UV degradation. They are made of ethylene, propylene and diene. E.P.D.M. lasts longer than natural rubber, but does not show wear like natural rubber; it looks new until it breaks. | Erickson Manufacturing Ltd. 30" Adjustable Industrial EPDM Rubber Tarp Strap | Size 30"