The model is F-19, here's a picture:

I had a moment of being really excited, because I was going to suggest we could split a pair. Unfortunately, after double checking it seems I'm missing the left side as well. Consider this a free bump from someone similarly in need, the cost of replacement rests is absurd.

I've got a used one in good shape. It's got the velcro attached - not sure if you had that kind or the one with the straps on the pads.