Compression rollers can generally be found on multi-point locks that are installed into PVCu doors. They may be positioned at various intervals along the faceplate of the lock and help to create an even weatherseal down the locking side of the door, thus helping to prevent draughts and water seepage.
Note: Compression rollers are primarily designed to create compression. Should security be priority on the door, Yale recommend multiple locking points be specified i.e. hookbolts.