Neoprene strip 3mm thick x 12mm wide

• Manufacturer: Various
• Product ID: Various

Provides resistance equivalent to a spring when used with a switch for a fire button

Supplier Links

https://www.amazon.co.uk/gp/product/B00MVQLC7G

Indicative Pricing With Allowance for P&P

You only need a few cm of this but you'll probably have to buy at least one metre. The product above is 5m long and costs £2.60, but you'll probably find shorter lengths on eBay for less, hence my indicative price of £1.

£1

Substitutions

You could use anything wider and cut it down. It does need to be about 4mm thick though to get a nice resistance.