Moonrays 91253 Solar-Powered LED Post Cap Light for 4x4 Posts, Black. Black plastic cap fits 4x4 posts, uses solar panels to charge battery and light up LED at night. Solar panel converts sunlight into free electricity, charges battery automatically. LED is energy-efficient, 2.4-lumen output runs up to 6 hours on a full charge. Designed to mount on top of 4x4 fence posts, includes (2) mounting screws for wood. Housing is constructed with durable plastic, includes clear plastic lens. Ready to work out of the box, no-wiring necessary - double-check battery is installed and place in the sun. (1) rechargeable battery is included per fixture(AA 600-mAh NiCd). The Moonrays (R) brand is a registered trademark of Coleman Cable Inc.