10 x 10 x 1/4 inches thick 6061 T6 aircraft aluminum with smooth machined and chamfered edges. Type III matte black hard-anodized surface for added durability and glare reduction. Six 3/8?-16 threaded holes, the film & still industry standard for large ball heads, magic arms and other grip equipment and fixtures. Six 1/4?-20 threaded holes, the film & still industry standard for small ball heads and fixtures. Platforms are designed with 5/16? countersunk through holes for spiking them to the ground or affixing them to wooden surfaces. Each has a curved 3 1/2 inch x 1 1/4 inch carrying handle that will comfortable fit a large hand. This handle will give you the option to quickly pickup and run with out removing smaller mounted gear. Platform bottoms are padded with non-slip 3/32? closed cell foam that enhances stability on rocky surfaces and protects delicate flooring such NBA basketball courts. Every plate comes with a 1 - 3/16? allen key; two 3/8? x 5/8? threaded studs; two 3/8?x 3/4? threaded studs; 1 - 1/8? allen key; two 1/4? x 1/2" long threaded studs.