Booms Fishing E1 Fish Bite Alarm, Electronic Buzzer with Blue LED, Black 1PC When fish bite, there's will be a bit of tension on the line to set the alarm off. Black volume knob for adjusting volume to fit your needs Sensitive yet accurate. Buzz when fish bite, but not so much so that wave caused by breeze can't set it off Perfect for night fishing. Besides the buzz, the little LED light will flash as well Fruity surface and rubber clip can not damage your fishing line, or any part of your fishing rod Easy to use. Can be clipped on rods up to 1.2 inches in diameter. Powered by 3 LR44 Batteries, batteries included