铝线卡扣。目前分几种：
Aluminum wire snap. At present, there are several kinds:
1.是手动打卡（样子很难看，而且密封性不好，易脱扣）
1. It's manual punching (ugly, poor sealing and easy to release).
2.圆铝丝打卡（圆圈型卡扣，小规格产品适用，大规格产品易脱扣）
2. Round aluminium wire punching (circle type, small size products are suitable, large size products are easy shiyany.89ix.com diandongmen.89ix.comtongmen.89ix.comqingxijii.89ix.comgangmumen.89ix.comerliu.89ix.comto release)
3.用的最普遍的长城卡（所谓长城卡就是卡线形状像长城城墙一样。此类卡扣结实，不易脱扣）
3. The most commonly used Great Wall Card (the so-called Great Wall Card is that the shape of the card line is like the Great Wall wall. This kind of card is strong and not easy to releas