4-1/2" lap joint type preformed exhaust clamp Made in the USA Aluminized steel for corrosion resistance A lap joint is an overlapping joint where the ID (Inner Diameter) end of a pipe is expanded and slotted and slips over the OD (Outer Diameter) end of the pipe, which is straight (that is, not expanded.) For instance, this clamp is for two pipe ends, one 5" ID (slotted and expanded), and the other 5" OD (not expanded). The ID end slips over the OD end and is secured and sealed by the clamp. Do not use this clamp for "butt joints", This is where two pipes with the same OD butt up against each other. You need to look for a butt joint type clamp for that. This clamp has an I block where the ends meet. This helps make for an even, uniform seal around all 360° of the pipe joint, eliminating exhaust leaks and noise. When traditional band clamps are tightened there will be a small gap where the two ends meet. Replaces: Heavy Duty Manufacturing 20A-450 Replaces Grand Rock PF-45A Replaces Riker TTA450
