COVID-19 Update (January 4th, 2021) — While our offices remain closed to the general public, Musson has resumed selected operations in compliance with county guidelines. Non-contact pickup remains available for customers who place their order online, by email, or by phone.
Most of our team continues to work remotely, and many employees are available through their direct extension. In an emergency, please contact us at COVIDemail@example.com or by leaving a voicemail in our general mailbox.
Replacement Focus Knob for your lens tube barrels (not for use with S4 jr). Also used in full size Source Four ERS fixtures as one of the two screws which attach the front barrel assembly to the reflector housing, the other is the Lens Tube Screw (accessories tab).