The Vixen P85 Pillar for the GP2, GPD2, and Great Polaris Mounts allows you to attach the mount to a pillar instead of a tripod. Pillars have a fixed height (33.5"/85cm in this case), but are more rigid than tripods, take up less ground space near the scope so you can get closer to the telescope, and eliminate the need for a half pillar.
The GP2 P85 pillar has a 4.0" (102mm) diameter and three support legs which are approximately 17.7" (45cm) long, creating a very minimal circle of ground coverage of less than 40" (102cm). It is the most common choice for Newtonian or Catadioptric telescope users looking for a pillar, but if you have a long refractor telescope you should likely instead choose the P110 pillar for added observing comfort at zenith.