Custom Design SQ 402 Speaker Stands The SQ 402 Speaker Support Stand Range are manufactured by the craftsman at Custom Design.By combining the ERW BS EN 10305-3 steel support columns or the solid hardwood supports with 4mm Inert Acoustic Steel top plates and 4mm steel base plates , Custom Design have created a discrete. rigid speaker support stand. Mass loading the steel support columns with Inert Filler adds 7kg to the final mass, we recommend 1 bag of Inert Filler per column, improving the performance of your SQ 402 Speaker Stands. AWAITING NEW IMAGES Top Support 165 x 180mmBase Plate dimensions 220 x 260 x 4mm steel.6mm Clear Glass Bases are manufactured to British Safety Standard BS EN 12105-2 and are available as a optional extra.(£20.00)M8 Zinc plated Alen Key adjustable base.