uxcell 5/16 inch x 18 Carbon Steel Serrated Hex Flange Lock Nuts 20pcs Thread Size: 5/16"(D); Product Name: Hex Flange Nut; Material: Carbon Steel Weight: 114g; Package Content: 20pcs x Hex Flange Nut Main Color: Silver Tone; Height: 7mm/0.28"(Total.Height) Hex Size: 13mm/0.5"(Hex.Width); Flange Diameter: 17mm/0.75" Grade: 4.8; Thread Count: 18