This standard functional desktop calculator with a large 12-digit display takes up little space on your desktop and fits easily into your briefcase or desk drawer. Item specifics: Powered by the dual power supply: light energy and batteries (not included) Size: 5.51*4.76*1.57in Weight: 4.41Oz(125g) Quality Promise: Lifetime Warranty: If anything at all goes wrong with your calculator, We've you a full refund or send you a replacement absolutely free, no return required Functional keys Instructions: ON/AC: turn on/clear M+/M-: memory Plus or minus MRC: Combination of [MR] and [MC] [MR]: Recall the current memory register value [MC]: Clear the memory register (set to zero) When you press the key once, the [MR] key was activated, when you press the key twice, the [MC] was activated