WIMBERLEY SK-100 Sidekick Quickly converts a standard high quality Arca Swiss ball head into a gimbal type mount Provides easier tracking and photographing of birds and large animals Anodized 6061 Aluminum, Powder Coated Aluminum, Soft-touch knobs, stainless steel fasteners Made in USA. Assembled in Charlottesville, Virginia Suitable for a variety of large telephoto lenses. See http://tripodhead.com/products/sidekick-compatibility.cfm for compatibility