Abstract: A cassette for attachment and use with an infusion pump apparatus. The cassette head having a low profile cassette head for attaching to the infusion pump apparatus and a flexible reservoir attached to the cassette head that can be filled with a fluid to be administered to a patient. The reservoir is enclosed in a flexible cover attached to the cassette. The flexibility of the cover and the reservoir inhibits the cassette head from disengaging from the infusion pump apparatus and allows the infusion pump apparatus to be primed by squeezing or pressing the cover and reservoir.