Wristbands take the prize as the most common new tech medical and health wearable form factor. We’ve written about scads of single-purpose and multifunction wristbands developed to track blood glucose level, mood, sleep quality, opioid overdose and much more. Smartwatches with medical monitoring technology are also plentiful, with frequent and significant developments by Withings and Apple. Fitness tracking wristband from FitBit and Garmin command a huge share of the wristband wearable market.

Busch Ltd’s BlueFox-Lifeline Wristcomputer notches another vital capability on the wristband capability scoreboard: drowning detection. The BlueFox-Lifeline wristband, which the maker claims is “adjustable to fit a toddler’s wrist or the wrist of an NFL lineman,” is available with a yellow, blue, grey, or red band. Parents or owners can program the wristband using PC software for depth and duration.

If the wearer goes deeper underwater than the programmed depth — as measured by an integrated pressure sensor — for longer than the programmed duration, two things happen. First, the wristband flashes a bright white LED to warn the swimmer. If the swimmer remains beyond the time and depth presets, the BlueFox-Lifeline launches a gas-filled balloon that travels to the surface at a rate of 3-feet-per-second. The bright-orange balloon sounds a 100-decibel alarm when it hits the surface and flashes the LED white light continuously.

The BlueFox-Lifeline wristband isn’t intended for remote contact or alerts; there is no wireless transmission feature. The company stresses that the device doesn’t replace “effective supervision and safety measures.” All parents and grandparents know how easy it is to lose track of a fast-moving toddler or young child during pool parties and water recreation spots. The maker suggests the drowning detector is also useful for elderly people and people at any age, including both swimmers and non-swimmers who may be in or near the water.

The BlueFox-Line lists for $350 but is on sale currently for $200. You won’t want to test the device or have it deploy casually; the single-use cartridge that holds and launches the signal balloon is costs $56.