1. & Large Furniture Leg Levelers:This commercial quality heavy duty furniture leveler comes with strong steel T-nut to lock and stablize the straightener, each can support max 330LBs,a set of four supports furniture weight 1320LBs! Fits for heavy furniture such as cabinets,tables,beds,workbench,sofa,chairs and more. 2.Adjustable Leveling Feet:1.75' long steel insert with 3/8-16' thread; Large Commercial Quality 1 3/8'' Diameter 1/2' Thick Base and Fully Adjustable Height from 3/4' to 1 3/4' for Maximum Support and Adjustability. 3.Protect Your Floors: Universal Nylon bottom that work for all floors such as hardwood/ tile/ carpeting floors. Comes with separate high density thick felt for hardwood floor to protect floor from scratches or harsh noises. 4.: For furniture legs with existing 3/8''-16 thread, simply screw in the leg leveler to adjust the height. Or, pre-drill a 1/2' hole and insert the Locknut with mounting screws ,stabilize the leveler and adjust to the desired height. T-nuts and installation screws are included.