It's a BodyBilt chair, with their Linear Tracking Arm.[0]

The chair has a moderate tractor seat, which forces you to sit properly, and not slouch. But that also means that you can't really relax in the chair, because it hurts in the crotch. There's also an inflatable lumbar support.

I used an Aeron for many years. It's much cooler looking, but the BodyBilt is more comfortable for long term use.

0) https://www.backbenimble.com/bodybilt/closeups/closeup_all_a...