4" Tire Plug String Type Insert Large Fat Brown Box of 50

4 Inch Tire Plug String Type Insert Large Fat Brown BOWES TR 37499 Box of 50. These inserts can be used in passenger or truck, radial or bias-ply tires. Made of a butyl rubber, these inserts are very strong, allowing easy insertion through steel belted radials. String-type inserts are temporary repairs, sealing by compression only. (Passenger length for 4” inserts; truck length for 8” inserts.)