These bottles are designed for storage of solutions and are ideal for media preparation. The 9.5 liter (2½ gallon) and 13.25 liter (3½ gallon) sizes are in a conventional bottle shape. The 19 liter (5 gallon) and 45.5 liter (12 gallon) sizes are similar in design to a carboy. The 19 liter size is weight controlled to 15 lbs. maximum for ease of handling. The necks are tooled to increase mechanical strength and for uniform stopper fit.