M3590CS-SBX Steel Cross & Side Box Corner Mounting Plates Powder Coated Black - Installation Mounting Kit for Cross Box and Side Box Application.

M3530CS Cross & Side Box Coupling Adapter Plate Installation Mounting Kit for Cross Box and Side Box Application.

Coupling Clamp Style Bolt on Mounting Kit is designed for Mounting Side Boxes to Cross Boxes.

For Installation Instruction see our Installation Catalog: 

Description Sheet: www.truckbox.com/images/PDF24/C-Page 84.pdf