Type B seat mounts are designed to "lock" into the post. Engineered to prevent unintentional detachment * Heavy-duty bushing with peripheral bearing system and exclusive "crush ribs" are individually sized for exact fit * Tubing is precisely-sized and satin-anodized finished. Tubing comes in several styles. Pedestals come in several lengths, including patented "J-Slot" * Precisely positioned locking tab positively locks post to base. Wedge? bushing locks in with a tight, solid fit. 2-Point stainless steel riveting strengthens the bushing * Strong base design has reinforcing ribs and improved profile to withstand the toughest conditions. Bead blasting closes aluminum porosity. Brushing process provides long-lasting high-sheen finish