Product Information Name: Knurled Head Thumb Nut Material: Stianless Steel Surface: Untreated Specification:M3 M4 M5 M6 M8 Size:M*D*H Example: M2.5xD12xH12 (thread inner diameter 2.5mm*outer diameter 12mm*height 12mm) The following information is measured manually, please prevail in kind, mind careful to shoot!