Identify the host system
Record the door or window series, material, profile and the location where the fitting will be used. If the system is existing, a clear photo and drawing can help the supplier identify it.
Match the fixing details
Centre distance, spindle, backset, handing, fixing pattern and load conditions may affect fit. Ask which dimensions must be measured and whether the information is suitable for the exact system.
Confirm finish and use
State the environment, use frequency and finish direction. Do not infer corrosion class, fire rating or security performance from appearance; request current documentation for the exact model.