The pull pin can make different materials closely connected, like the close connection between metal material and plastic, the close connection between laminated glass and metal material, etc. in the application of unique flexible materials, the wholesale and manufacturing industry of double drum rivets will slightly change the tensile strength of the journal, and then use a large boss bolt itself to separate the clamping load to a large area. Once I was The leather products are closely connected with aluminum profile by using this basic theory. Closed mouth acne type pull nails have a new quality now. Due to the unique structure, closed comer type pull nails make the bolt management center have leak proof characteristics. In order to better ensure that the closed comer type pull nails have leakage and sealing characteristics around the diameter of the bolt or the diameter of the shank, a layer of ductility is applied to the side of the shin side of the bolt boss house Polymer material, this way makes closed acne bolt have sealing, moisture-proof, air tightness and other characteristics, this feature for the application of nail opened a new sales market. Once I applied various kinds of different polymer materials to the end of closed mouth acne and start type pull nails. As a result, the sealing property of the nail has made me deal with many situations waiting for solution in front of me. Such advantages have made the "excellent joint characteristics" widely praised by the nail broaden a big step.