TFT’s SHO-FLOW® BLUETOOTH® generates its own power using an unobstructed water driven turbine, with a built in stream straightener, that will pass debris up to 1″ (25mm) in diameter. Starting at 50 gpm (200 l/min), the turbine generates power needed to supply a BLUETOOTH® connection to any smart device. Choose units you want displayed from your smart device; gpm, gps, l/min or l/sec. Full flow range 50 – 300 gpm (0.8 – 5 gps) (200 – 1150 l/min) (3.33 – 19.16 l/sec).