One of the big problems with word processing on the Spectrum is connecting the computer to the kind of printers that will give you good quality print. The +3 has a built in printer port, so all you need there is a printer lead but for the 48K/128K/+2/+2A users an interface is what's needed.
The Parallel/Centronics Printer Interface comes as a plug-in unit, connecting to the back of the computer. The lead included in the package connects to any of the top parallel printers. All you do is load in the software and you're away!
So, what exactly can you print from your Spectrum to the printer? You can use any of the top word processing packages (Tasword, Devpac, etc) to create your documents and then, using the print option, send the information to your printer. You can also print out hi-resolution screen dumps to a dot-matrix printer. For people who want to use their Spectrum as a wrod, erm word, processor this interface is an essential purchase.