Diff between popit n poppet valve?

hi there! can anyone tell me pls the difference between "popit valve" n "poppet valve"? or r they exactly the same? I am translating a technical manual for an industrial shear equipment -a large one- from english into spanish n I have a line that reads "4 way or popit valve - check for leaks" but I cant find the meaning of popit valve, I only find it for poppet...so, any ideas here? tks in advance!