Arrow 72627AKN Indy-Race Dark Aluminium Slip-On Muffler w/Carbon End Cap for KTM 390 Adventure 20-23Arrow Indy Race Slip On Exhaust KTM 390 Adventure The Arrow Indy Exhaust was inspired by the fierce competition witnessed at the famous US circuit. It features a unique, diamond shape muffler that is unlike anything else on the market. This innovative diamond shape design allows the Arrow Indy exhaust to have reduced dimensions compared to traditional shaped exhausts. The exhaust also features a significant weight reduction without having to