If you will be obtaining and selecting the correct product size: 20 pieces in a box. 5/16"-20 UNC threaded shaft is 0.74" (18 mm) long and the round base is 0.63" (16 mm) in diameter. If you are unsure your local hardware store can help you determine the correct replacement size. Please note that there may be measurement errors. STRONG BASE MATERIAL HOLDS UP TO #250 WEIGHT: The small black base is made of ABS on the bottom and has a non-slip design to withstand the weight of common indoor and outdoor furniture. The galvanized metal screws are reliable, strong and more rust-resistant for long time use. VERY EASY TO USE:You can use the existing 5/16-20 threads to screw directly into the floor leveler, or re-screw into the 5/16 inch (approx. 1.9 cm) holes, screw into the leveler and level your chairs and tables to avoid wobbling and protect your furniture from damage. BEAUTIFY BROKEN FURNITURE AND ENJOY COMFORT: Suitable for all types of flooring, including wood, laminate, hardwood, tile, carpet, extra noise avoidance, and can be moved easily. Suitable for tables, boxes, cabinets, desks, chairs, washing machine raises, bathroom cabinets, shoe cabinets, TV cabinets, tea makers and other furniture, practical and convenient. MADE IN USA: This leveling replacement is recommended for indoor or outdoor furniture legs made in the USA. Detailed instructions in the size comparison chart