Designed as a field test instrument for ASTM D 3385. Unit has two stainless steel rings measuring 12 in and 24 in dia x 20 in high (304.8 x 609.6 x 508) mm. The rings incorporate a double thickness welded top edge for increased stability when driven into soil. Assembly includes 1/2 in (12.7 mm) thick aluminum driving cap with centering pins to simplify setup, 2 - 6.0 in (152 mm) square neoprene splash guards and 2 Mariotte tubes (3,000 mL and 10,000 mL).