In one example in accordance with the present disclosure a printer cartridge is described. The printer cartridge includes at least one backpressure chamber to provide backpressure to a fluid during deposition of the fluid onto a print medium. The printer cartridge also includes multiple fluid chambers in fluid communication with the at least one backpressure chamber. A fluid chamber provides fluid to a portion of a printhead. Adjacent fluid chambers are selectively in fluid communication with one another via valves.