These springs are made from high-carbon steel, which is also known as music wire. They are zinc plated for corrosion protection. The height of the spring is slightly taller than a stock JLF spring.
These springs were custom manufactured in NJ using an authentic JLF spring as the base for the design.
Suitable for Sanwa JLF series joysticks which come with a 0.9lb spring stock, using this spring will result in a firmer feeling stick.