Ball transfer units (BTU) are ball transfer table components that consist of a large, load-bearing ball that sits atop smaller balls inside of a hemispherical cup. Ball transfer tables are used in applications that require manual rotation or positioning, as they facilitate the quick and easy handling of products and materials. Some ball transfer units have support springs to absorb momentary shock loads from these conveyor line transfers, while others have sealed balls to prevent the ingress of debris and liquids. Low-profile ball transfer units and BTUs with drains or exit holes are also available.  

Most ball transfer units are made of carbon steel, stainless steel or nylon. Carbon steel or plain-carbon steel is a commonly-used steel that contains carbon as its main ingredient. Stainless steel is chemical and corrosion resistant, and can have relatively high stress ratings. Nylon 6/6 ball transfer units are also available. Some are glass-filled to add structural impact strength and rigidity. In addition to BTU material type, maximum load, weight, ball size and barrel diameter are important parameters to consider. Typically, the maximum load and weight are measured in pounds (lbs) while the ball size and barrel diameter are specified in inches (in). Ball transfer units that are listed in units of measure such as kilograms (kg) and millimeters (mm) are also available. 

Ball transfer units differ in terms of mounting style. Choices include disk mount, flange mount, pipe mount, press or drop-in, and stud or bolt mount. Disk-mounted or saucer mount BTUs have a mount at the center or near the center of the assembly. With flange-mounted products, the flange is located at the top or closest to the ball on the body assembly. Pipe-mounted ball transfer units are sized and designed to be inserted into a standard pipe size. Press or drop-in products are assemblies that are designed to be pressed into a mounting hole. Ball transfer units with an integral mounting bolt or stud are also available.