A chrome plated zinc flange make this an attractive flush mounted fishing rod holder by Perko. Anodized aluminum tube holds the fishing rod, and a soft black flange gasket and integral flip-up cap deter water when the holder is not in use. The flange measures 4-1/4" x 3-1/2", while the length under the flange is 8". The tube measures 1-5/8" inner diameter and 2" outside diameter. Securing bolt size is 1/4 inch.