Tru-Flate Chembond Tube and Bias Ply Tire Repair Patches ensure the repair gets done rightFor use on tubes and with bias ply tires only - do not use on radial tiresWhen patching a tire, always prep the surface with a liquid buffer/cleaner then rough up the surface with a manual or rotary buffer; a thoroughly prepared surface ensures patch adhesion and safety3-1/8 inch round patches feature a pure rubber flow into injury and can be applied with universal cement or an electric vulcanizerBox of 20 patchesTru-Flate is part of the Plews & Edelmann group. Plews Manufacturing and Sales Corporation was originally founded by R.G. Plews in 1927. At that time, the railroad industry was the primary focus for the company's extensive line of oil cans. As the transportation industry went from trains to passenger cars and trucks, Plews shifted their focus to developing the tools necessary to service this new mode of transportation. Fast forward 90 years and Plews has become part of Plews & Edelman. Today, Plews & Edelmann is a leading designer, manufacturer and distributor of a broad range of automotive parts and tools sold to the vast majority of mass merchant, retail auto parts stores and wholesale automotive parts and industrial distribution outlets, worldwide.