To prepare the indicator that tells you when the product is finished: Hold the tab and peel off the silver coloured foil from the top of the refill exposing the blue liquid use-up indicator

liquid solution

making it compatible with thousands of devices while delivering exceptional performance

Memory backup power

flash units

Shop Motion Welcome Door Bell With Music or "DingDong" Battery or Power Supply Personal Care To prepare the indicator thatIt designed for using in shop, with "DingDong" sound. And also has 32 short music and welcome sound in Chinese. It uses AAA battery(included) or power supply (not included). It designed to stick on to the wall, or screw into the wall. The volume can be changed. Features: The button at the back to change from Chinese Voice to Alarm (DingDong) or Music. Sound change button located at the back. Volume change button located at the back. ON OFF button