Since it is compact, it can be used easily from small to large aquariums. A simple design that emphasizes functionality and cost. Easy to measure by simply scooping in saltwater. 2-color display for optimal specific gravity range at a glance. (Specific Gravity Measurement Range: 0.04 - 0.030); Product Size: W 3.7 x H 4.3 x D 0.6 inches (95 x 110 x 15 mm).