Check the listing for details. 25pcs Threaded Inserts 1/4-28 UNF 2.5D Helical Stainless Steel Thread Repair. Condition: New. Listed at 16.14 USD. Thread Size: 1/4-28 UNFEffective Length (after Installation): 2.5D = 15.875mm / 0.63"Free State Length (before Installation): 11mm / 0.43"Free State Outer Diameter (before Installation): 7.8mm / 0.31"Type: HelicalMaterial: 304 Stainless Steel25pcs x Threaded InsertsDescriptions:304 stainless steel has good corrosion resistance, rust prevention, high hardness, and excellent oxidation resistance. It is austenitic stainless steel, which is non-magnetic or slightly magnetic. With self-tapping sleeves, the same screw can be used continuously.Features a certain of elastic, and provides an even load on the thread. Wire thread inserts have self-tapping capability without pre-tapping the base metal. Large contact surface with finished products, strong tensile force. Strong resistance to vibration, no deformation.