Solid steel construction,19 gauge steel plate housing, 11 gauge steel plate door, floor or wall mount. Concealed, tamper-proof hinge, LCD display, hidden lock with two keys. Electronic combination can be programmed with codes up to 8 digits. Combination can be changed for maximum security. Electronic keypad uses four AA batteries (included). 0.3 Cubic Feet. Outside: 7.87 in H x 12.2 in W x 7.87 in D. Inside: 7.8 in H x 12.13 in W x 5.51 in D.