This cap press fits over the rear of the Wildcat Mk1&Mk2 block and protects against dirt ingress. There is a magnet built in which holds the cocking lever fully open to enable a magazine to be inserted much more easily while the gun is pointing safely down.
Made from solid sintered Nylon and dyed matt black.
The cap is friction fit and has a 1mm tongue which slots between the block and stock for extra security. (See photo.) Most Wildcats will have sufficient gap for this to fit without modifications but yours may not. If it doesn't then the tongue can be removed with a sharp knife but this leaves the cap relying on friction.