HP 21 Black Original C9508FN Twin Ink Pack in Retail Packaging
Page Yield: 300* Pages
Replaces: HP 21, C9508FN
At LD Products we know nobody enjoys shopping for ink and paper supplies. That’s why we offer our original HP 21 ink in one convenient twin pack! That’s right… now you can purchase a low-cost C9508FN twin pack comprised of two HP 21 black ink cartridges quickly and affordably. Each original HP 21 cartridge in this set is backed by the prestigious HP name and reputation and tested to ensure premium print quality on every page printed. LD Products extends free shipping on all orders over $50. 100% Satisfaction Guarantee.
This item is guaranteed to work with the following printers:
*Average cartridge page yield in accordance with ISO-19752.
LD Products is not endorsed by, and not affiliated with, HP®. LD Products is an independent retailer and not within the authorized seller network of HP. This product is covered by LD Products' warranty and does not come with the HP Limited Warranties.
Name Brand (OEM) Cartridge
OEM stands for original equipment manufacturer, meaning the cartridge was made by the same
company that made your printer. Name brand cartridges are designed to work with specific
printers and are sometimes the only option if your printer is new or uncommon.
Many printer manufacturers follow the razor-and-blades business model, selling their printers for
cheap while marking up the cost of their cartridges, which often results in higher priced ink.
Name brand cartridges work extremely well and are covered under a warranty by the printer
LD-Brand Compatible Cartridge
A compatible cartridge is a brand new printer cartridge built by a manufacturer other than your
printer. It’s like buying the generic version of the genuine brand. Most are designed slightly
different from the name brand but they will still fit in your machine and print a full yield, just
like the OEM.
Compatible ink is much cheaper than the name brand. Compatible suppliers don’t have to worry about
the additional costs that hinder OEMs like new printers or firmware, which lets them keep prices low.
Premium compatible cartridges from LD Products match the quality and output of the name brand for
less and are backed by a lifetime guarantee.
LD-Brand Remanufactured Cartridge
Remanufactured cartridges are name brand cartridges that have gone through one cycle of use. After
use, the cartridge is recycled, acquired by a remanufacturing facility and put through a rigorous
professional refurbishing process where it is disassembled, cleaned and tested for quality. It’s
then refilled, tested again and brought back to life. Buying remanufactured cartridges prevents one
less cartridge from entering the landfill.
Remanufactured cartridges are much cheaper than the name brand. It’s far more cost effective to
refurbish a previously used cartridge than create a new OEM from scratch.
Premium remanufactured cartridges from LD Products match the quality and output of the name brand
for less and are backed by a lifetime guarantee.
What's the difference between ink and toner cartridges?
What printer does it work with?
How it works
Uses a series of nozzles that spray tiny drops of ink onto the page.
Uses static electricity and heat to bond toner powder to the page.
Who uses it?
Commonly used by families, small businesses, and photographers.
Large businesses and schools.
What cartridge size should I buy?
Extra High Yield
A standard yield cartridge is the most common cartridge size and since it prints a smaller number of
pages compared to a high yield or extra high yield cartridge, it can often be purchased at a cheaper
price. If you don’t print regularly, standard cartridges are a great choice.
A high yield (also called high capacity) cartridge contains more ink or toner than a standard printer
cartridge and since it prints more pages, it is more expensive too. However, if you normally print a
lot, getting a high yield cartridge is a better value.
An extra high yield cartridge contains even more ink and costs more than a high yield cartridge.
This is more suitable for document-heavy office users. These cartridges aren’t as common as standard
yield or high yield cartridges - not every printer has an extra high yield option!
How many pages will my cartridge print?
A cartridge’s page yield is the estimated number of pages you can print. Page yield is based on 5% page
coverage. This means that the quoted page yield is based upon printed pages where only 5% of the page has
been imprinted with ink. For example, a short memo has approximately 5% coverage. If you have a cartridge
that has a yield of 500 pages, it can print 500 pages of that short memo. If you are printing letters,
photos or graphics, your coverage will vary greatly and your page yield will drop significantly. Since
everyone’s printing habits are different, actual page yield can vary from user to user. LD brand cartridges
are filled to the same capacity and will print the same number of pages, if not more, than the name brand
cartridge. You can find the estimated page yield of your cartridge in the specs table on our cartridge
Cartridge Yield Type
Cost Per Page
How long will my cartridge last?
The shelf life of a printer cartridge can vary depending on what sort of cartridge you are using. The average
shelf life for a compatible cartridge is 36 months, while the shelf life for a name brand cartridge is only 24
months. If your printer uses ink cartridges, the ink inside can dry out over time, which can cause your printer
to clog. To prevent clogging, we recommend printing once every couple of weeks to keep your cartridges primed.
Due to the plastic nature of toner powder, toner cartridges will not dry out the same way an ink cartridge
would, but internal cartridge components can wear with repeated use.
Does my LD cartridge come with a chip to read accurate ink levels?
Yes, almost all LD cartridges are equipped with a new chip that will accurately read the ink levels on your
printer’s display. There are some remanufactured cartridges that may not accurately read in your printer but
they are still filled to capacity and will print the same number of pages as a name brand cartridge. If you
know roughly how long it takes you go to go through a name brand cartridge you can use that as your baseline
to manually track cartridge usage.
How easy is an LD cartridge to install?
LD cartridges install the exact same way as the name brand and they are guaranteed to fit and function in the
same way too!
Does using an LD cartridge void my printer's warranty?