Shutterfly's Splint Boot is a Black Market item that was removed. It used to cost 5 passes and gave you a special coat called marquis, and some other bonuses. marquis comes in chestnut, bay(snip) and bay (star,snip)

the Shutterfly's Splint Boot gives you:

stamina: +6, speed: +4, dressage: +4, gallop: +2, trot: +2, jumping: +6