4U Rack Space 18" Depth Rack Mount Drawer for Audio, DJ, and IT Server rack cases.

ProX T-4RD-18 MK3 This rack-mountable sliding drawer can be mounted to any Standard 18-inch Rack Case or Cabinet. These high-quality steel drawers are electro-static protected. It has a sleek powder-coated finish, it comes in a variety of options including 2U, 3U, and 4U. Each rack drawer slides out smoothly and can be locked. It has a programmable 3-digit key combination lock (with included reset key – see included instructions)...
https://www.proxdirect.com/products/view/744