Alan, not trying to splash Andy's this looks like the shorter version. From other's comments and talking to Jeremy of SPP Pipes, the other 2 being the outboard NR21 and RS21 both with longer stingers with the RS21 most recommended for heat racing. I'm still testing on my NR powered Dragon M11 against a "brand X" pipe. BTW, I find this hull incredible in its driving and handling attitude!