These printers use the 51608 cartridge:

DEC DecJet 1000

DEC DecJet 2000

DEC DecMultiJet 1000

DEC DecMultiJet 2000

Olivetti OFX 2035

Olivetti OFX 2045

Olivetti OFX 2100

Olivetti OFX 2200

Olivetti OFX 3200