The 4 hole - inside corner bracket with dual support is an external, die-cast fastening method that creates a 90 degree connection. There are two adjacent holes on each side of the bracket. The dual supports provide additional strength while the slotted mounting holes allow for greater adjustability between the connecting profiles. Brackets with a slot tab on the support help to line up the profile with the bracket and prevent rotation. It requires no machining services and can provide infinite positioning along the profile T-slot. The suggested mounting hardware can be found on the "Suggested Hardware" tab.