The F.A.S.T. 401 Adjust-O-Matic by YoYoFactory is a yo-yo released in 2009. This aluminum model features the same F.A.S.T. 400 Series shuttle system as the older 401k from 2005, along with a rounded H-shaped profile.
As with the 401k, the user can adjust the responsiveness of the yo-yo by turning the dials on the outer hubs to set the shuttles to a flush or recessed position on the inside, with ninety settings for each body half.
- The Adjust-O-Matic, along with the F.A.S.T. 401 SD, were the very last yo-yos produced by YoYoFactory as part of the F.A.S.T. 400 Series.