Prob suggest doing it on the cheap, the grubsteak i feel might not be the concentrator you really want, still got do some panning after the fact. I use a small 20cm wide sluice by 70cm long lined with black rubber grooved matting easily sourced at Clark rubber using just a hose from the garden tap. Sure it won't get every tiny speck but it will flush out the ironstone and blondes from the cons pretty quick using a scoop. I gave my grubsteak to my nephew who does use it to help him out before panning so it will work but at the price id get the cheaper more effective option I've outlined. Advantage of the grubsteak is it can be used as a sluice i guess.