[2 Base Sizes Available] For 4x4 vinyl posts, please must remove the inner base before installation.For 4x4 wooden posts-actual size: 3.5x3.5", actual size of our product's base: 3.6x3.6". For 4x4 vinyl posts (Remove the inner 3.5x3.5" base first), actual size of our product's base: 4.1x4.1". Measure your post caps beforehand for seamless installation on fences, decks, gates, or mailboxes no electrician needed! [Dual Lighting Modes Warm White (3000K) or Cool White (6000K)] Customize your outdoor vibe with 24 high-brightness LEDs (12~12.5 lumens)choose Warm White for cozy evenings or Cool White for crisp modern flair. Perfect for outdoor lighting and garden decor,deck decor,fence decor,patio decor. The transparent lens amplifies light, turning your yard into a radiant oasis from dusk to dawn.