Borla 2016 Chevy Camaro SS 6.2L Dual NPP Tip AdaptersBorla 2016 Chevy Camaro SS 6. 2L Dual NPP Tip Adapters These 2. 75" diameter Tail Pipes are intended to add the Dual Mode Exhaust (NPP) valves to Borla systems 11920, 11921, 140687, and 140688 that did not come with NPP valves. They feature 4" polished T 304 stainless steel tips. They can only be used with mufflers that have dual tips exiting the mufflers. These pipes replace the outside tail pipe on each muffler. Outside tail pipe on 11920, 11921,