The 4 hole - rectangular transition flat plate with flush offset is an external fastening method that connects profiles within the same product type (either fractional or metric) but of differing series. One of the bolt holes is slotted, as opposed to circular, to allow for an added degree of adjustability when lining up profiles. The offset design creates a flush connection between the different sized profiles. It is a durable connection that is reconfigurable and reusable and can provide infinite positioning along the profile T-slot. The suggested mounting hardware can be found on the "Suggested Hardware" tab. Tip: Use a double slide-in economy T-nut to save time and money. Pre-load your hardware prior to connecting profiles to simplify your assembly.