Worn like a wristwatch, this wireless immersion alarm instantly alerts you when a child falls into water. The immersion sensor secures to a child's wrist with a locking buckle, so it can't be removed or fall off. The instant the wristband is submerged in a pool or lake, a piercing 98db alarm sounds (as loud as a smoke detector) at the base station up to 150' away, giving adults a chance to react quickly, even if they are indoors. Because it's wearable and portable, the alarm can be used when visiting friends or relatives who have pools. It is the only wristband alarm that has passed the Good Housekeeping Research Institute's rigorous testing. Base station plugs into AC; wristband battery lasts 3-4 years. Includes one wristband. For ages 6 months-10 years. Base station: 7 3/4" H x 4 1/2" W x 6" L. (1 1/2 lb.)