Marlex Hopper Kit Model HBCKH Assemble Marlex Hopper Kit to your A-51 or A52 Hand Sluice as per diagram. On the A51 sluice place the hopper over the sluice box and lower it into the sluice making sure that the front edge of the hopper buts up to the ribbed rubber matting. (note the hopper will overhang the edge of the sluice