From Manufacturer
Support your large telephoto lens with the Acratech Long Lens Head with Leveling Base Kit from B&H. This setup will have you moving freely while keeping the lens perfectly balanced, which you could not do handholding the lens otherwise.
The Acratech Long Lens Head is designed to support super-telephoto lenses as long as 600mm f/4.0. The CNC-machined Long Lens Head weighs less than 1 lb and features an Arca-style quick-release clamp that's compatible with plates from manufacturers such as Arca-Swiss, Kirk, R.R.S., and many others.
The clamp is indexable, which means it can be rotated in 90° increments by loosening the rubberized knob. This enables easy use of cameras without lenses that have lens collars, and facilitates 90° sideways tilt (rather than front-to-back tilt). While the head is specifically designed for use with extremely long telephoto lenses that are mounted with a lens collar, this feature ensures that even if you're using multiple cameras in the field, you don't need to transport other heads besides the Long Lens Head when you want to mount a camera body (with a smaller lens) directly to your tripod & head.
The tension control is fully adjustable to suit heavier and lighter loads, and the head tilts 90° in two directions. Degree markings are engraved, for precise control over panoramic adjustments. All knobs are secured so they cannot vibrate loose and fall off.
The Acratech Leveling Base is a leveling base that fits between the tripod (or stand) and the tripod head, and can be used with any tripod that features a 3/8" head screw. This device allows for the photo or video head to be quickly leveled, independently from the tripod.
At its center is an oilless and greaseless ball that will not attract or hold dirt and debris. It allows 10° movement in any direction, and features smooth knob action for easy and secure positioning.