BT1688 Digital Battery Tester Accurate measurement across common sizes: tests C, AA, AAA, D, N, 9V and 1.55V button cells to determine the battery status reliably. Easy to use: fix the battery in the appropriate position and the tester begins to work, displaying the reading on an easytoread LCD. Threezone display: the LCD shows three zones—red for poor, yellow for weak, and blue for good—allowing quick assessment of battery health at a glance. Durable construction: built from quality plastic and stainless steel for reliable use in household or DIY environments. Practical value: a helpful tool for managing batteries in everyday devices and projects, ensuring you know when a replacement is needed. Use scenarios: Home electronics: check remotes, clocks, toys, and flashlights to know when to batteries. DIY projects and workshops: verify tool batteries, RC devices, and sensors before starting work. Emergency readiness: inspect batteries for flashlights, radios, and other critical devices to ensure readiness.