Printrbot Tri-Rod Mod Improved Bottom Piece

This is an improved version of the bottom no xl piece for the printrbot simple 1405 tri-rod mod (http://www.thingiverse.com/thing:575393). It uses the attachment mechanism of the printrbot simple stabilizing legs (http://www.thingiverse.com/thing:366326). The guide hole for the bottom screws is larger than on the normal piece, making it easy to slide the screws in. Also, the piece is thinner where the screws attach so that M3 20mm screws are long enough to attach it.