Hydroton GMHT10L Hydroponic Grow Rocks, 10 Liter Bag (Discontinued by, 10-Liter, Brown Strong pebble structure doesn't crush Color packaging 8-16mm pebble size range Measures 16-4/5-inch length by 12-2/3-inch width by 3-2/7-inch height Hydroton grow rocks Strong pebble structure doesn't crush Records high and low points for both temperature and humidity Measures 3.2-inch in length by 3.2-inch in width by 8.6-inch in height