This compatible Brother P-Touch TZE-421 label cassette contains 8m of top quality black on red tape that is 9mm in width. Producing a product that can genuinely be called an alternative to the Brother P-Touch TZE421 is of utmost importance to our manufacturers, and this is shown nicely in the finished product.You can expect this TZ421 label cassette to be compatible with all of the same great handheld Brother label printers including the Brother P-Touch PT-E300VP.