Classy Caps FS100W Fairmont Solar Post Cap, 5" x 5", White High performance solar lights stays lit for up to 10 hours Lights up automatically every night 2 high output led's for brilliant white light 1 long life AA Niamh rechargeable battery included Will fit over an ACTUAL 5"x 5", 4"x 4" or 3.5"X 3.5" post