A piece of buttress material and an end-effector of a surgical instrument including features which can aid a surgeon in properly and quickly attaching the piece of buttress material to the end-effector. In various embodiments, a piece of buttress material can include retention features which can be engaged with portions of an end-effector to releasably retain the piece of buttress material to at least a portion of the end-effector. Similarly, an end-effector can include features configured to engage portions of a piece of buttress material to releasably retain the piece of buttress material to the end-effector. In at least one embodiment, more than one piece of buttress material can be releasably retained to an end-effector.