Attwood Lock'N-Pin Post Base - Proven by decades of experience these stainless steel Lock N Pin Post Base are the perfect economical seat mount base for the boater needing and affordable and durable option. These will work in many different boating applications and styles and will exceed expectations. Stainless Steel Finish With Steel Lip Tube; Dimensions: 7in x 7in; Non-threaded; Nylon bushing;