This universal fit letterplate from yale provides an excellent external weather seal and an internal draught seal to protect the home from the outside elements internal brushes reduce heat loss and an external foam seal prevents weather ingress its sleeve width of 254mm ensures that it can take full a4 size post without bending a common problem for other letterplates internal and external thumb handles make it easy to open the flaps and its fully sprung flaps have high endurance tested to 4000