The 3M - K15 Scotchlite Micro-Balloons are high-strength microspheres that are composed of water-insoluble, chemically stable, soda-lime/borosilicate glass. They are nonporous making them ideal filler in most resin systems. For weight to volume reference, 2 oz. = quart container, 4 oz. = ½ gallon container, 8 oz. = one gallon container, and a 1 kg container is the size of a box 9 " x 9 " x 9 ", and a 5 lb container is the size of a box 12 " x 12 " x 12 ".