We can confirm that all cartridges are the same size. 29 XL Black cartridge holds 18ml of ink, colours - 15ml each. We have listed the combined capacities for all the packs. We have two of our top value packs available with both holding 10 cartridges. One is a colour mixed pack and the other is a twin pack with 2 extra blacks. Depending on if you use more black or more colour in your printer. All cartridges are guaranteed for a year and these are the best value packs for your Epson printer. Please see the available printers on this page.