An end effector assembly for use with a surgical instrument, the end effector assembly comprising: a fastener cartridge, comprising: a plurality of fasteners removably positioned in said fastener cartridge (5750; 5850), wherein each said fastener is configured to move from an unfired position to a fired position; a deck; a longitudinal slot, a first notch on a first side of said fastener cartridge; and a second notch on a second side of said fastener cartridge, wherein said first notch and said second notch are positioned on opposite sides of said longitudinal slot; a layer of material releasably secured to said fastener cartridge, wherein said layer of material is at least partially captured by said fasteners when said fasteners move from said unfired position to said fired position, and wherein said layer of material comprises: a first mount on a first side; and a second mount on a second side, wherein said first mount extends into said first notch and said second mount extends into said second notch when said layer of material is secured to said fastener cartridge; characterised by said first notch and said second notch being defined in said deck, wherein said first notch is positioned on an edge of said fastener cartridge, and wherein said second notch is positioned on an opposite edge of said fastener cartridge; and a first attachment feature and a second attachment feature, wherein said first attachment feature and said second attachment feature are configured to attach said layer of material to said fastener cartridge, and wherein said first notch and said second notch are intermediate said first attachment feature and said second attachment feature. a fastener cartridge, comprising: a plurality of fasteners removably positioned in said fastener cartridge (5750; 5850), wherein each said fastener is configured to move from an unfired position to a fired position; a deck; a longitudinal slot, a first notch on a first side of said fastener cartridge; and a second notch on a second side of said fastener cartridge, wherein said first notch and said second notch are positioned on opposite sides of said longitudinal slot; a layer of material releasably secured to said fastener cartridge, wherein said layer of material is at least partially captured by said fasteners when said fasteners move from said unfired position to said fired position, and wherein said layer of material comprises: a first mount on a first side; and a second mount on a second side, wherein said first mount extends into said first notch and said second mount extends into said second notch when said layer of material is secured to said fastener cartridge; a plurality of fasteners removably positioned in said fastener cartridge (5750; 5850), wherein each said fastener is configured to move from an unfired position to a fired position; a deck; a longitudinal slot, a first notch on a first side of said fastener cartridge; and a second notch on a second side of said fastener cartridge, wherein said first notch and said second notch are positioned on opposite sides of said longitudinal slot; a layer of material releasably secured to said fastener cartridge, wherein said layer of material is at least partially captured by said fasteners when said fasteners move from said unfired position to said fired position, and wherein said layer of material comprises: a first mount on a first side; and a second mount on a second side, wherein said first mount extends into said first notch and said second mount extends into said second notch when said layer of material is secured to said fastener cartridge; a first mount on a first side; and a second mount on a second side, wherein said first mount extends into said first notch and said second mount extends into said second notch when said layer of material is secured to said fastener cartridge; characterised by said first notch and said second notch being defined in said deck, wherein said first notch is positioned on an edge of said fastener cartridge, and wherein said second notch is positioned on an opposite edge of said fastener cartridge; and a first attachment feature and a second attachment feature, wherein said first attachment feature and said second attachment feature are configured to attach said layer of material to said fastener cartridge, and wherein said first notch and said second notch are intermediate said first attachment feature and said second attachment feature.