Type of pressure vessel

This might be a dumb question, but how would I describe the below type of pressure vessel to someone over the phone?  I'm working on a side project and need a vessel with a removeable flange top like the one below, but I feel kinda dumb describing it as a "vertical pressure vessel with a flanged top thingy on it".  Thanks in advance!

http://www.precisionfiltration.com/images/products/vcs-856-344%20housing.jpg

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