Detail of one of some text stamped on the flowmeter. It reads

Pat. 2709366
Nos. 2709755
Others Pending
Mfg. Code 83475

A cursory Google search shows that Pottermeter became (or perhaps was a division of) Potter Aeronautical Co. and later Hoffer Flow Controls

F-1 rocket engine LOX flowmeter Pottermeter stamp

Photo Credit Eli Ziv
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