Disclosed is an improved coupling for cement heads. One exemplary cement head includes a first module comprising a first end, a first outer surface, and a plurality of first protrusions extending radially outward from the first outer surface, each of the plurality of first protrusions comprising a first profile in which (i) a first engagement surface faces axially away from the first end and (ii) a first support surface forms a first oblique angle relative to an axis; and a bridge configured to engage the plurality of first protrusions.