Ball head
From Wikipedia, the free encyclopedia
A ball head is a metal or plastic contraption placed on top of a tripod that increases stability and provides faster, more accurate rotation for the photographer. They are also lighter than traditional three-way pan-tilt tripod heads.
With fewer parts and a much simpler mechanism, ball heads are usually preferred by more advanced photographers. However, they are usually quite expensive due to the precision-made pieces inside and the detailed finish outside -- most are more than $200 USD.