2-7/8" diameter stanchion tube, 9" diameter 6 hole base plate. One piece casting design for mounting seats as low to floor deck as possible. Compatible with Garelick hardware. Provides solid base of support for a variety of seat hardware. Mounts Garelick fore and aft seat slides and 360 swivel spider combinations. Fore and aft seat slides: 22000, 75080, 75081, 75082, 75083. Swivel spiders: 99023, and 99036. Anodized protective finish.