This anodized aluminum focus knob guard for the Preston HU4 handset attaches right onto the back of the hand unit, allowing you to place the handset down on a surface without bumping the knob position and changing the focus. The guard also improves holding ergonomics for your right hand. If you are using the pre-printed focus rings, it also protects these against chipping and wear and tear.
Two 4-40 screws are included. Simply remove the two corresponding screws from your handset and install the guard with the provided screws. Made in Canada.