Swing arms with motion adapters are ideal for computer usage from both the driver and front passenger seats. (C-MD-112) | Side support arms add upper pole support for premium top level stability. (C-HDM-401) | The heavy-duty vehicle specific mounting base mounts to existing OEM seat bolts for easy installation (C-HDM-185 | Heavy-duty height adjustable poles bolt to the vehicle specific base. precision machined parts eliminate metal-to-metal contact and allow for smooth movement during height adjustment. (C-HDM-202) | Packages are complete and you must order as-is. there will be no substitutions on any part