The adapter is made of a sturdy polyethelene plastic with holes drilled to fit on a standard wheel heads with bat pins spaced 10" apart. Two bat pins are set in the top of the adapter spaced 6" apart, allowing 8.5" and 10" Hydrobats to fit snuggly onto the adapter. Smaller Hydrobats like the 8.5" and 10" are great for production potters making multiples of small cups and bowls.