Jamb Jack Insert III for doors. Priced each individually, sold in multiples of 30.
Truth Hardware's Jamb Jacks are a specially designed fastening system for mounting door and window frames into rough openings. Jamb Jacks replace shims used to square the window or door in the rough opening. By simply turning the Jamb Jack screws, all necessary adjustments can be easily made while the unit is in place.
