FS: Helper Springs

I have a set of nearly new, only about 100 mi, 550 lb leaf spring helpers from Hellwig. I bought them to fix the sagging rear, later to find out that the problem was a broken leaf spring, so I replaced the leaf packs entirely. They also work well to eliminate axle wrap by stiffening up the leaf springs. I'd like to get $50 for the pair of them since they are just about new, I still have the box and instructions they came with.