The Flat Post Cap is designed to fit deck, fence, and dock posts. It is compatible with dimensional, composite, and vinyl post sleeves. It is also compatible with CCA (pressure treated) wood. We have done extensive accelerated testing with the materials we use in our products and have found no degradation or negative effects. The post caps themselves are extremely durable:

Waterproof / Weatherproof / Salt Air Resistant / Hail Damage Resistant
Heavy duty, aircraft-grade aluminum die-cast fixture
Corrosion Resistance from Alodine™ coating / Epoxy primer prior to powder coating
UV protection built into high quality powder coating formulation
Finally, our Flat Post Caps come with our unbeatable 10/30 year warranty, up to 3X longer than “comparable” post caps found at big box stores. Our Flat Post Cap Lights do triple duty, offering protection and ambiance while adding safety and security to your home. The lights are low voltage, energy-saving, and use our own Plug-N-Play technology, which makes installation a breeze. The Flat Post Cap is lighted with 4 or 6 CREE LED lights per side ( with 5 lighting configurations available. Light one side, two sides, three sides, or all four to suit your deck design and provide light where you need it most. The total light output is dependent on the number of LEDs on each illuminated side of the cap. Cap sizes 4 1/8″ and smaller house 4 LEDs on each side, emitting 15 Lumens per illuminated side. Cap sizes 4 9/16″ and larger hold 6 LEDs per side, emitting 25 Lumens per illuminated side. The Top Light Flat Post Cap is designed to fit deck, fence, and dock posts. It is compatible with dimensional, composite, and vinyl post sleeves. It is also compatible with CCA (pressure treated) wood. We have done extensive accelerated testing with the materials we use in our products and have found no degradation or negative effects.