Mortise handle sets are where the lock set requires a pocket or “mortise” to be cut from the door to fit a box like cartridge into the width of the door. The mortise lock originated in Europe but is often found in high end residential construction here in the India Specific door prep is required for the door to accept a mortise handle set and we recommend you hire a professional for this installation as it is extremely specific and requires precision woodworking. If you are not sure if your door will accept a mortise handle set please give us a call and we will be happy to confirm that his type of lockset will work with your specific doors.