The SP20R-PW is a specially cabled 20 W solar panel. It is often used for system configurations that have higher-than-average power requirements, or in higher elevation and latitude locations. The SP20R-PW is very similar to the SP20-PW except that it contains an on-board voltage regulator, allowing the panel to supply power directly to a user-supplied battery mounted inside a Campbell Scientific prewired enclosure (PWENC).