Abstract: A mechanic's tray assembly for holding tools and small parts, and removably adherable to both horizontal and non-horizontal surfaces. The tray assembly includes a shallow-walled tray and a pair of C-shaped support tracks fixedly secured to the tray. A pair of removably-adhering assemblies, independent of each other and preferably having magnets, are slidably and pivotally held on the C-shaped support tracks by support arms. The support arms have cylindrically-shaped holes through which the C-shaped support tracks extend. The cylindrically-shaped holes engage and grip the support tracks by means of a cantilever moment produced at the tube-shaped holes, thereby enabling the tray to be held at a desired tray angle.