FastCap Assembly Blocks (2 pc set) The Assembly Block is an innovative product that allows you to build your cabinets in no time and with no assistance. Set up the Ass. Blocks according to the size cabinet you are building. Place each panel in an Ass. Block and tighten it in place using the handle to adjust. Align corners and screw them together. You’re done! Lift the cabinet and start on the next one!