These boxes are nearly indestructible! Heavy duty hinges and a rubber watertight gasket make this a long lasting home for your prized flies. The stainless steel hinge pins won't wear out like traditional plastic hinges. Each box has 12 spring loaded compartments on one side and slit foam on the other. The 12 compartments are expandable to six with the removable dividers. The foam side holds 132 flies. Measurement: 7.8" x 4.5" x 1.8"