The button "Power? you can press it on or off. Display: LCD display with back light Max Capacity: about 40kg/88lb Min Capacity: 10g/0.02lb Powered by 1.5V X AAA battery Size: 13*9*2.5cm Weight: 3.6oz (Batteries included) Package Contents: 1 X Electronic Scale 2 X 1.5V AAA Batteries