A modified version of the Eppley PSP pyranometer has been designed for use on ships and moored buoys. Seventeen have been built by the Eppley Laboratory for the Upper Ocean Processes Group and deployed on buoys in the deep ocean. Six others have been incorporated into IMET systems mounted on U.S. research ships. A comparison study between four Improved METeorology (IMET) PSPs and one standard PSP shows that the two are completely equivalent in performance. The IMET PSP is more corrosion resistant, compact, robust, and is easier to mate to electronics modules. It is available from the Eppley Laboratory for about the same price as the standard PSP.