The Libec AD-75 is a 75 mm adapter that allows a Libec video head with a 75 mm ball base to be mounted on a tripod designed for a 100 mm ball (bowl). Many professional tripods, pedestals and dollies are built with a 100 mm bowl, while lighter fluid heads for smaller camcorders and mirrorless or DSLR video rigs use a 75 mm ball, so this ring lets a camera operator use a smaller, lighter head on existing larger legs rather than buying a second tripod. The adapter is a black machined ring that sits in the 100 mm bowl and provides a 75 mm seat for the head's ball. It is a small, simple accessory, useful for production companies, rental houses, broadcasters, schools and churches that mix Libec heads and legs from different series. Libec describes it simply as an adapter of Libec 75 mm heads for 100 mm ball diameter tripods; compatibility with other brands' heads or bowls is not confirmed. The head and tripod are not included.