Blind/Hidden Inside Corner Bracket for 20mm V-Slot/T-Slot Aluminum Extrusion 25x25x10mm (Pack of 5) Compatible with: Misumi 5 Series, Openbuilds V-Slot, Openbuilds C-Beam, and other standard v-slot/t-slot 20mm aluminum extrusions Not compatible with 80/20 20 Series Material: die-cast zinc bracket, stainless steel M5 * 4mm set screws Make blind or hidden 90 degree connections Package contents: (5) brackets; (10) set screws