These are a discontinued spring that we had made for the Longshot kit, but didn't suit our purpose:
They were designed with too few coils, which makes them quite stiff but prone to buckling if left cocked for too long.
At 2 bucks each they are under our cost, I just want to get them out of my cupboard.
Please don't ask a bunch of questions about them, just read the description (please).
They may suit the budget concious, or someone making a homemade or something.
I haven't tried, but they may fit applications like the triple shot, PAS, etc, where a LS spring can be used.
Please bear in mind they are seconds items, and priced accordingly.