At Greenmill AC, we stock H-Frame kits (305mm); and Big Foot H-frames in 305mm/12" and, for bigger loads, 450mm/18". Our range also includes adjustable duct supports; and Minifoot products in 110mm and 160mm, in addition to a 110mm Minifoot kit with 250mm channel. H-Frames are quick and easy to install, versatile and economical. Click on products to learn more. Fast UK-wide delivery.