IMPORTANT! Clearance between faucet bottom to faucet base needs to be more than 8 inches. This item fits M22/M24 threaded Kitchen faucets, but doesn't fit most Bathroom Faucets. Troubleshooting: Not sensing/ running water automatically 1. Fully charge the item for at least 4 hours before installation 2. Wipe clean the sensor windows. Make sure the upper sensor and the bottom sensor are not covered by drops of water or vapor. 3. Objects with high reflection sometimes can interfere the faucet sensor, please check if there is any object with high reflection nearby the sensor, and move them a bit farther. 4. Try moving the sensor window to a different direction, for example, the sensor window can face to the wall so it won't detect too much movements when it's not supposed to be activated. 5. Make sure that the indicator light at the upper sensor flashes just Once when it detects your hand. In case of continuous flashes or no flash at all, you need to charge the battery.