Mainly because the shop called me and I asked about it and he's like, what rockshox?? We got a fox float rp23 ordered for you. I'm like, well that'll work too I guess, so I told him to keep the fox ordered. I've never used either one and read good reviews on fox floats so that's what I'm goin wit... He also had better things to say about the fox than the rockshox so that helped convince me also.