website:https://www.jhmindustry.com/
Shanghai Jian & Mei Industry and Trade Co., Ltd. is the company which manufacture and export fasteners and metal hardware, founded in 2006, with import-export authority. Now, 80% products export to all over the world and 20% sell in domestic market.
ISO 7380 bolts are use throughout, when practical. ISO 7380 is a type of machine screw with a domed allen head, also known as button head (BA) allen. The six-sided hole for the allen wrench is one size smaller than a regular allen head. So an M6 allen bolt takes a 5mm allen wrench, while a M6 button head allen bolt takes a 4mm allen wrench, an M5 allen takes a 4mm wrench, while an M6 BA takes a 3mm wrench, and so on. The button head looks and feels nicer, but strips the wrench hole easy. ISO 7380 buttonhead allen bolts were used from 2003 to 2009. Before that the bolt style was pan-phillips and regular hex.
Flange hex bolts are used throughout the 2010 and later models. The flange is like a built-in washer under the hex. They work great but look ugly. The 2010-2011 parts manuals still contain the older buttonhead allen bolts. When the parts become available the 2010-2011 manuals will be updated. Until then if you order certain screws/bolts for a 2010-2011, you will get some that work the same but look way different.
Spring ring means lock washer.