LakeSport Seat Mount- 2-3/8 inch Locking AO-Aluminum, with Friction Control, 3 Degree Tilt, ABYC Code - AO, Installed Height - 5/8 inch, Bulk Packaging. Hardware is Engineered to Exceed ABYC Standards Type A/Operator Models lead the industry with these features: Ergonomic positive-locking handles with stainless steel components inchJ-Slot inch locking channels (on adjustable-height models) are the safest manual adjustment available. All Models are reinforced for strength: All LakeSport posts are swaged and welded to the bases Bases have underside ribs for superior strength.