A set of ink cartridges is configured to mount in a cartridge mounting portion of a recording apparatus in an insertion direction. The set of cartridges includes a first and a second ink cartridge, and each cartridge includes a main body and a particular protrusion positioned adjacent to a bottom wall of the main body and extending from a portion of the main body in the insertion direction away from an ink chamber. The main body includes a first wall, the ink chamber, a communication portion disposed at the first wall; a second wall disposed opposite the first wall, and the bottom wall. The ink chamber is disposed between the first and second walls. A first length difference between a first length of a portion of the bottom wall extending from a rear end of the bottom wall of the first ink cartridge to an end of the particular protrusion of the first ink cartridge and a total length of the first ink cartridge is different from a second length difference between a second length extending from a rear end of the bottom wall of the second ink cartridge to an end of the particular protrusion of the second ink cartridge and a total length of the second ink cartridge.