The Kirk NC-300 Replacement Lens Collar is specifically designed for the
Nikon 300mm f/4 AF-S lens.
It is designed to provide maximum lens support, with quick, accurate, smooth
rotation and positive locking in any position.
Machined from lightweight 6061-T6 aluminum, the base is made to fit a Kirk
Arca-Swiss-type quick release clamp. In addition, instead of only one point of
support, the NC-300 provides an additional point of support for the lens at the
other end of its plate.