As mentioned, Escape lounges will soon be branded Centurion Studios. The small Centurion Lounge at SEA was originally a Centurion Studio, but American Express made no further use of the brand until now. This is mentioned in the new offer terms of the refreshed Platinum card. This benefit also extends to Skymiles Reserve cardholders when flying on a Delta ticket purchased with an American Express card.
Escape Lounges – The Centurion® Studio Partner
This benefit is available to Platinum Cards. Additional Gold Cards and Additional Green Cards on your Platinum Card account are not eligible for complimentary access. Card Members receive complimentary access to any US location of the Escape Lounges. Card Member must present his or her valid Card, a boarding pass showing a confirmed reservation for same-day travel on any carrier and government-issued I.D. In some cases, Card Member must be 21 years of age to enter without a parent or guardian. Card Members may bring either (i) up to two guests or (ii) immediate family members, which are spouse or domestic partner and all children under the age of 18, as complimentary guests. Delta SkyMiles® Reserve and Delta SkyMiles® Reserve Business Basic and Additional Card Members receive complimentary access to all Escape Lounge locations when flying on a same-day Delta-marketed or Delta-operated flight. The eligible flight must be booked on a U.S. issued American Express credit card and Card Members may bring up to two guests at a per-visit rate equal to the guest fee of the respective Escape Lounge location. Card Member must adhere to all house rules of participating lounges. Card Members and his or her guests will receive all of the complimentary benefits and amenities afforded to the Escape Lounge customers, as well as access to purchase non-complimentary items. Some product features may be subject to additional charges. Escape Lounge locations are subject to change.
Some discussion here:
Escape lounges to become Centurion Studios?