I tested these with a conbination of white sand, blonde sand, black blasting medium, black sand, crush lead shot and some fine gold and I didn't lose any gold or shot and didn't have hardly any thing to pan. Out of a half gallon of all of this mixed together it left maybe half a cup to pan. I had weighed the lead and gold before and it was all there.
I read somewhere that it could be improved by puttin some ribbed mat in it but it didn't say where.
One of these has the end cut out and the other has a grizzly and spraybar.