Poolguard PGRMSB Safety Buoy Above Ground Pool or Spa Alarm Designed for use in any above ground pool or spa and some small in-ground pools The only floating alarm NSF Certified to the ASTM F2208 Pool Alarm Standard Floats on the water and uses Sub-Surface detection technology to detect 18 or more pounds Includes an in-house remote receiver that works up to 200 feet away Model: PGRM-SB