Fits externally over 4" x 4" Posts and also fits 3-1/2" x 3-1/2" with adjustable inside tab. May be installed internally onto 5" x 5" posts or externally using Part Number #5560 SKU:   5553 Weight:   2 Quantity:   6 Colors:   Related Items: 60 Watt Transformer 88 Watt Transformer Lighted Post Cap Kit 5" Lighted Post Cap Adaptor 14 Gauge Wire 12 Gauge Wire