BO = Bolt-On Slip On
CE = CF Cone End Cap
DUAL = Dual Mufflers
FS = Full System
HE = High Exit (no passenger peg
HS = Half System
O2 = O2 Sensor Bung
SINGLE = Single Muffler
SO = Slip-On (with tailpipe)
4x2x1 = 4x2x1 Full System
3/4 System = YZF-R1 includes "Y" pipe
3/4 System = SV1000/S uses OEM rear cylinder header
AL = Aluminum Sleeve
CF = Carbon Fiber Sleeve
SS = Stainless Steel Header, Mid Pipe, Sleeve
Ti = Titanium Header, Mid Pipe, Sleeve