Seachoice Clamp-On Oarlocks 1/2" Zinc Pr 50-70521 by Seachoice $10.29 1 2 3 4 5 6 7 8 9 10+ Quantity Quantity Add to cart Seachoice Clamp-On Oarlocks 1/2" Pair #50-70521 Oarlocks made of bright zinc plated steel. Resists rust. Shank is 1/2" x 2". Inside diameter: 1-3/8". It fastens securely to oars with one adjustable bolt.