We fitted this product to a ledged and braced bathroom door in our own residence. We wanted a way to lock the suffolk/thumb latch from the inside, but have a means to effect an emergency release from the outside as we have family with disabilities. Most bathroom door locks with an emergency release are designed for mortice fitting into the door thickness and are unsuitable for surface fixing on a 19mm thick ledged door. The choice of models in black is scarce. This product was ideal. It fits in with the traditional look and does not need cutting extra notches out of the architrave or frame which most other latches or locks require. Fitted in minutes as a replacement for the standard screw on stable. Easily converted to have an emergency release by simply drilling the hole for the pin all the way through the door so another similar pin (or meat scewer in our case) can be pushed through the hole fro the outside to remove the pin and open the thumb latch.