Feature: The product can used to prevent screw loosening. Surface is treated with galvanizing, the product has good anticorrosion performance. GB standard,this cotter pin can be adapted to more products. After the screw nut is tightened, the cotter pin is inserted into the nut slot and the bolt tail hole, which can effectively prevent the screw from loosening. The product is durable and easy to use. Specification: Material:Iron with galvanization Standard: GB Application: Screw, Bolt Model: M4*20, M4*25, M4*30, M4*35, M4*40, M4*50(Optional) Package list: Model Product dimension Package list M4*20 d: 4mm; l: 20mm 50pcs M4*25 d: 4mm; l: 25mm 50pcs M4*30 d: 4mm; l: 30mm 50pcs M4*35 d: 4mm; l: 35mm 50pcs M4*40 d: 4mm; l: 40mm 50pcs M4*50 d:4mm; l: 50mm 50pcs Note: The actual product color may deviate from the photo due to light. There may be a slight deviation in the measurement of product dimensions. 1、The product can used to prevent screw loosening. 2、Surface is treated with galvanizing, the product has good anticorrosion performance. 3、GB standard,this cotter pin can be adapted to more products. 4、After the screw nut is tightened, the cotter pin is inserted into the nut slot and the bolt tail hole, which can effectively prevent the screw from loosening. 5、The product is durable and easy to use.