The HydraBaths 200501 Air Control Knob is designed for use with the Hydrabath Standard Series Air Controls. This knob comes with an O-ring and has a scalloped white finish. In addition, it ensures a tight seal that won't leak or let air escape, and it is made to be simple to install.
For use with Hydrabath Standard Series Air Controls
Alternate Part Numbers - _200501 , 391585, 55-157-1110