KEX KX-002 repair patches are designed to work with inner tubes and other rubber products to create a permanent puncture repair. When properly installed, KEX inner tube patches stretch with the inner tube during inflated to keep its repair bond in place during use. Each box contains 40 units of 2-1/4 inch round vulcanizing patches for automotive, truck and farm tire inner tube repair. For best results, use KEX KX-511F flammable chemical cement. Use a repair unit that is at least 1/2 inch larger than the injury on all sides.