Interchangeable tools for surgical instruments

A disposable loading unit comprising:

• a housing configured to be coupled to a portion of a surgical instrument, said housing having a first lateral side and a second lateral side;
• a carrier coupled to said housing;
• an anvil movably supported for selective movement relative to said carrier in response to opening and closing motions from the surgical instrument to selectively move said anvil toward and away from said carrier;
• a cartridge body configured to be removably received within said carrier;
• a tissue measuring platform pivotally coupled to said cartridge body for movable travel relative thereto;
• an indicator base movably supported by said cartridge body for axial travel relative thereto;
• a gear assembly operably interfacing with said tissue measuring platform and said indicator base, such that movement of said tissue measuring platform causes said indicator base to move axially relative to said cartridge body;
• and
• a plurality of thickness identifiers on said indicator base corresponding to particular tissue thicknesses and viewable from at least one location in said housing when tissue having said corresponding amount of tissue thickness is clamped between said anvil and said cartridge body.