A surgical instrument, comprising: a handle portion; a body portion extending distally from the handle portion and defining a first longitudinal axis; a movable handle disposed on the handle portion and in mechanical cooperation with a drive member; a tool assembly including an anvil, a cartridge assembly and a contact surface, the tool assembly being supported adjacent a distal end of the body portion; a drive beam (750,802) including a plurality of layers (750a-750e), at least one layer having a proximal engagement portion disposed adjacent a proximal end thereof and being configured to engage a portion of the drive member; a closure apparatus disposed adjacent a distal end of the drive beam, the closure apparatus including a cutting surface (766, 808) thereon, a cross-section of the closure apparatus being generally I-shaped with horizontal portions, said horizontal portions being configured to engage the contact surface of the tool assembly, whereby at least a partial actuation of the movable handle moves the closure apparatus distally into engagement with the contact surface to approximate the anvil and the cartridge assembly, and the drive beam (750,802) including between four layers and six layers, at least one layer of the drive beam being made of stainless steel, wherein each of the plurality of layers (750a-750e) of the drive beam include at least one cutout disposed therethrough, the drive beam being part of a disposable loading unit, and characterised in that portions of the closure apparatus comprise a plastic surface provided by a plastic coating, overmolded plastic, or plastic caps at least partially covering said horizontal portions. a handle portion; a body portion extending distally from the handle portion and defining a first longitudinal axis; a movable handle disposed on the handle portion and in mechanical cooperation with a drive member; a tool assembly including an anvil, a cartridge assembly and a contact surface, the tool assembly being supported adjacent a distal end of the body portion; a drive beam (750,802) including a plurality of layers (750a-750e), at least one layer having a proximal engagement portion disposed adjacent a proximal end thereof and being configured to engage a portion of the drive member; a closure apparatus disposed adjacent a distal end of the drive beam, the closure apparatus including a cutting surface (766, 808) thereon, a cross-section of the closure apparatus being generally I-shaped with horizontal portions, said horizontal portions being configured to engage the contact surface of the tool assembly, whereby at least a partial actuation of the movable handle moves the closure apparatus distally into engagement with the contact surface to approximate the anvil and the cartridge assembly, and the drive beam (750,802) including between four layers and six layers, at least one layer of the drive beam being made of stainless steel, wherein each of the plurality of layers (750a-750e) of the drive beam include at least one cutout disposed therethrough, the drive beam being part of a disposable loading unit, and characterised in that portions of the closure apparatus comprise a plastic surface provided by a plastic coating, overmolded plastic, or plastic caps at least partially covering said horizontal portions.