Model: HP Deskjet 310 Printer, HP Deskjet 520 Printer
Operating System: Windows 95 (Note: might work with other versions of this os.)
HP DeskJet Driver version 6.5.9 for Windows 95. This driver corrects the incompatibility of printing on COM 10 envelopes that the HP DeskJet experiences with the original Windows 95 driver. The product supported by this driver is the HP DeskJet 500C, 520, 540, 550C, 560C 310, 320, and Portable.