The SNORKEL All 12V Gold Dry Washer: This is the only dry washer on the market with a 12V DC turbofan (14,000 rpm) inside and therefore requires the 4 inch diameter hose vertically up to 6.5 feet to supply it with clear air. The high-frequency vibrator (3500 rpm) gives 100% linear motion with tray direction for smooth riffle tray flow. The hopper screens to the required -1/4" flow and can run up to 2 yd/hr. This dry washer for gold prospecting & mining plays an indispensable role especially with this new technology invention. The tray has 7 "flow management" riffles but also has 600 micro riffles (1/4" holes) where the very fine gold is trapped under black sand.