UNITS- Switch metric/imperial system, HOLD- prevent deviation, MEMORY- Viewstored, SAVE- Store 5 datas, CLEAR- one key to zero, POWER- Power on/off, open/close backlight. All buttons are IP54 waterproof and dust-proof. Durable button-The number of keystrokes is limited to 1 million times. Rare high-precision digital display measuring wheel on the market. The unit of measurement has FT / IN / M / CM / ' / " .Can be used by professionals. Adopts a precise gear structure design. the forward count increases, and the backward count decreases, effectively avoiding errors. Through 2 tims folds can be folded to 16 inches into a backpack(included) for easy carrying and transport. Unfolded it extends to 40 inches. Stronger bracket, Perfect joints, Threaded TPR tires, Increased friction, Original location marker, carrying bag.