This is the knob on the right side of LPL 4x5 enlargers that is at the end of the fine focus attachment. The knob is secured on the shaft by a small D-shaped spring clip. If your original knob is broken, this is the correct OEM replacement. Includes securing clip. Since the same fine focus assembly is an optional accessory on the LPL 7700 series of enlargers it may also be needed as a replacement for those enlargers.
Fits the following: