U Packer 4mm Red (50/Bag)

Red U Packers for the precise positioning of window and door frames. They can be easily slid around existing fixings without removing screws, helping to maintain accurate datum and line during set-out.Each packer is colour-coded for quick on-site identification. The rigid, non-compressible polymer provides a stable bearing under typical frame loads, while the internal comb design ensures a secure grip that resists movement during tightening and final fixing.The material is non-absorbent and non-staining, ensuring a clean, professional installation against both frames and substrates. These U shaped shims help establish plane quickly with fewer stacked pieces. Used singly for confident pack-off or combined with finer sizes to tune level and reveal, they maintain consistent plane across the bearing face to protect frame profiles and finishes.The 4mm thickness is suitable for larger gaps or firmer fixing where a more pronounced correction is needed.