The AP-70CP is a center post that is required to connect two, three or four of the Apollo gym stations into a standalone unit. For example, the AP-71MP Multi Press Station and the AP-71LE Leg Entension/Leg Curl Station requires the AP-70CP Center Post to create a two stack multi-station gym. The Center Post is included when you purchase the AP-7200, AP-7300, AP-7350 or AP-7400 gyms which are all sold at your nearest Flaman Fitness.