Need new seat bases for your boat These bell pedestals are the way to go. Get the seat post with the base included or each part separately. These pedestals have fixed or adjustable height. Both have a super-satin anodized-finish aluminum tube and include a 9-diameter bead-blasted and powder coat finished base and seat mount with friction knob swivel control. Fixed-Height Pedestal: 9 rise. 2-3/8 diameter tube Adjustable-Height Pedestal: 14 to 20 manual adjust rise with friction knob control.Hard anodized seat spiders come in two styles to fit your needs. Both have friction control and positive locking handles. One base has a fixed position, the other slides. Fixed: 2-3/8 dia. tube Sliding: 2-3/8 dia. tube Ideal for many applications, this durable and sturdy line of bell pedestal seat posts has satin anodized tubing and brushed aluminum bases. Bases are 10 diameter. 9 Seat Post: 2-3/8 diameter tube (Requires seat base listed above) Cancer and Reproductive Harm- www.P65Warnings.ca.gov. Type: Pedestals.