While the new Casio G-SHOCK Ref. 6900-PT80 by John Mayer has sold out, you can still find similar watches and dupes available to buy online.
Hodinkee x G SHOCK x John Mayer x Ed Sheeran
John Mayer debuts second limited-edition watch in new G-Shock, Hodinkee and Online Ceramics collab - The Manual
Online Ceramics x Hodinkee x John Mayer x G-Shock : r/onlineceramics
Online Ceramics x Hodinkee Casio G-SHOCK Limited Edition
John Mayer debuts second limited-edition watch in new G-Shock, Hodinkee and Online Ceramics collab - The Manual
in Hand Casio G-shock Ref. 6900 Wrist Watch by John Mayer X Hodinkee for sale online
HODINKEE Partnered With John Mayer For A Classy G-Shock Ref. 6900 Timepiece - SHOUTS
Hodinkee John Mayer Gshock Collabany takers? - Page 4 - Rolex Forums - Rolex Watch Forum
John Mayer Unveils First-Ever Watch Collaboration with G-Shock
Casio G-SHOCK Ref. 6900 by John Mayer