There are (2) I/O ports, for pneumatic supply/exhaust. They would generally be used as pneumatic clamps or supports to hold a workpiece at a specific height. The threaded portion and round clamp are just the extended section and can be customised to suit your needs.

As an example, the round clamp could be used to pneumatically pull down on a piece of material, using a compressor, prior to machining. More suited to production environments or batch runs.

Hope that helps