tacklife advanced laser measure 196 ft digital laser tape measure with mute function laser measuring device with pythagorean mode, measure distance, area and volume black&orange tacklife versatile features with multiple measurement modes to improve efficiency ✔20 groups historical datas this laser measure is able to hold 20 different historical values which is reasonable and perfect, lets you check and remember conveniently. you can also manually delete current data or all data that you unwanted. ✔switchable measuring units the default unit is meter, press the “unit” button can change unit among m/in/ft freely as your needs. it will remember the last unit setting after power off. ✔optional measuring reference front and rear measuring reference support you do various measurement like single distance measurement, auto area/volume measurement, pythagoras measurement and continuous measurement at your will. ✔other practical multiple setting the s2 laser tape measure displays 4 lines with backlight. thanks to funcions of max/min value, addition and subtraction and self-calibration, gives you more easier and faster measuring jobs done.✔laser class: class 2, <1mw power output. ✔battery type: aaa 2 x 1.5v