Staywell 300 - 4 Way Locking Cat Flap/Door - White 4 Way Locking: In Only, Out Only, In &amp; Out, Fully Locked Transparent flap with magnetic seal to prevent draughts Fits doors up to 2" thick Can be installed in thicker door/walls using Staywell 310 Tunnel Extensions Can be fitted into single or double glazed panels.