Make sure you are ordering parts or supplies for your waterbed type. A Hardside waterbed has wood or upholstered boards holding the waterbed mattress in place. This style bed is normally placed on a pedestal with or without drawers.
A hardside waterbed comes in 3 standard sizes:
Super Single 48" Wide - 84" Long
Queen 60" Wide - 84" Long
Cal King 72" Wide - 84" Long