HP have two sizes of ink cartridges. HP 301 black and colour standard capacity ink cartridges and HP 301XL black and colour high capacity ink cartridges. The ink cartridges in the HP 301XL have larger sponges so they can hold more ink and print more pages. Original HP 301XL ink cartridges effectively produce up to 2x as many prints than the standard capacity cartridges at a reduced price per page.
HP 301 Black - 3.5ml
HP 301 Colour - 4ml
HP 301XL Black - 8ml
HP 301XL Colour - 8.5ml
Unfortunately if you are buying HP 301XL remanufactured or refilled ink cartridges many sellers on eBay and Amazon are dishonest and are using standard capacity ink cartridges and putting an XL sticker over the top in the hope customers won't notice. However we only sell Ink Jungle refilled ink cartridges which always use XL cartridges with the larger sponges and have produced some images below to help consumers how to tell the difference between a fake 301XL and a real 301XL refilled ink cartridge.