This is an older model that is being phased out. We recommend the equally heavy duty yet lower-priced Oben ACM-2400 4-Section Aluminum Monopod as an alternative.
The Manfrotto 681B Heavy Duty Pro Monopod is appropriate for use with the largest telephoto lenses, such as the 500 f/4 and the 400 f/2.8.
It features both 1/4"-20 and 3/8"-16 mounting threads. Its three sections extend to 63.4", and it provides sturdy support.