|A2 Stainless Steel
Spring washers are locking washers that are used when there is a need to prevent a fastener from loosening as a result of vibration. They are also often called split lock or split ring washers.
A spring washer has a split in the washer section that when tightened each side of the split bites into the nut and the mounting surface. This “bite” prevents any anti-clockwise rotation from occurring under vibration.
The term “square section” refers to the end section of the split in the spring washer.
An imperial washer can be used in conjunction with all types of non-metric threads including UNC, UNF, BSW, BSF, BA etc.
A2 stainless steel is often referred to as 304 or 18/8 Stainless. 18/8 actually refers to the amount of chromium and nickel in the alloy - 18% chromium and 8% nickel.
A2 stainless is the most common type of steel used for the manufacture of fasteners and is suitable for general use.