(1) Cement head connection pup joint
Cement head connection pup joints are often used for cementing shallow large-size casings that do not use the inner pipe method for cementing. They are just bushing fittings used to connect bushings to small gauge tubing. They are subject to greater internal pressure than the bushings with which they are used. However, rubber plugs cannot be used for connecting pup joints. It should only be used on catheters or superficial casings.

(2) Single plug cement head
The single plug cement head is used to store a lower rubber plug (or upper rubber plug) before the rubber plug is pumped into the casing during the cementing process. The general practice is to install the lower plug and put it in front of the spacer or cement slurry. Then open the cement head, install the upper plug between the two inlets, and release the cement slurry after pumping. The main disadvantage of the single-plug cement head is that the circulation must be stopped in order to install the rubber plug after the mud circulation. This will cause the mud to produce gel strength and affect the displacement efficiency of the mud.
(3) Double plug cement head
The double-plug cement head can store two rubber plugs, and there is no need to stop the pump to install the rubber plugs. A pump stop is necessary only when switching the service line to the cemented line. The deposit/delivery system for the double plug cement head is the same as for the single plug cement head. The disadvantage of the double plug cement head is that for small drilling rigs, the lifting ring of the tap is often not long enough to load and unload the double plug cement head.