To save consumption of the coin battery of the CR1620 that is smaller than CR2032 this BED-H1 applies PULSE in adjustment of intensity at 10 settings. The practical reason of using the smaller coin batter is for just compactness of the push-button. Push either switch to turn ON/OFF the power in 2 seconds. If the power is left without cutting, it shuts off automatically after 3 hours. And when you turn on the power the sight starts at the same level of brightness as it shut off. The 5-meter immersible structure gives waterproofness to the body. You can handle this sight well owing to the compact body with a built-in weaver mount.