A removable, replaceable ring at the lower opening of {TAIL ~ the processing chamber} allows {HEAD ~ process} pumping speed to be tailored for different processes by replacing the ring 
A removable , replaceable ring at the lower opening of { TAIL ~ the processing chamber } allows { HEAD ~ process } pumping speed to be tailored for different processes by replacing the ring
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH