features · lowest backpressure measured ininches of mercury 200 cfm of all ... flows either direction allowing easy installation with 2 21/4 21/2 and 3 i.d systems ... from vibration heat and backfires with internaldrainage system to reduce corrosion ... 21108hkr 21106hkr 21109hkr 21107hkr inlet and outlet sizes i.d 2 21 4 21 4 21 ... flows either direction allowing easy installation with 2 21/4 and 21/2 i.d systems ... · improved engine efficiency results in better performance and economy · ... wrapped aluminized steel construction inlet and outlet part no sizes i.d case type ... 21005hkr 21006hkr part to page index 21004hkr 21005hkr 21006hkr 21007hkr ...