16" Underbody Toolbox Mounting Brackets, 1/4" Aluminum, Lightweight, Strong. For semis, flatbeds, trailers, box trucks.. 1x Pair of aluminum underbody toolbox mounting brackets. Flanges are not pre drilled due to frame and toolbox holes not being universal.Mount to frame or spacers to get desired depth. 16.25" tall and deep +. Leave them raw or sand and paint. Die scars are from being bent on press brake.