||A series of free-falling optical profiler intstruments, initially developed by Satlantic, but now distributed by Sea-Bird Scientific since the companies combined in 2011. The instruments, such as the original Profiler and the later model Profiler II, primarily determine ocean colour and other optical properties of the ocean. They can also provide calibration and validation data for ocean colour satellites. The instruments are fitted with ancillary sensors measuring water pressure, temperature, conductivity and instrument tilt. Data products include water-leaving radiance, remote sensing reflectance, energy fluxes and PAR. The instruments can be deployed in various configurations, such as free-fall, frame-mounted and buoy mode. Data logging and processing software are included. They can be fitted with optional WET Labs ECO Puck sensors measuring fluorescence, backscatter and turbidity. The instruments are depth-rated to 220 m and can operate in tempeartures ranging from -2.5 to +40 degC. In free-fall mode the descent rate ranges from 0.1 to 1.0 m/s.