A surgical fastener applying apparatus, comprising: a first jaw including a cartridge body housing a plurality of first and second surgical fasteners (130, 130 A, 130B); and a second jaw connected to the first jaw such that the first and second jaws are repositionable between unapproximated and approximated positions, the second jaw including a tissue contacting surface having a plurality of fastener forming pockets formed therein, each of the plurality of fastener forming pockets being configured and dimensioned to receive and effect the formation of the plurality of first and second surgical fasteners upon ejection from the cartridge body; wherein the plurality of surgical fasteners include: a plurality of first surgical fasteners, each of the plurality of first surgical fasteners having a first pair of legs terminating in penetrating ends, the first pair of legs being connected by a first backspan having a hump extending towards the penetrating ends, the hump defining a first height (H 1); and a plurality of second surgical fasteners, each of the plurality of second surgical fasteners having a second pair of legs terminating in penetrating ends, the second pair of legs being connected by a second backspan having a hump extending towards the penetrating ends, the hump defining a second height (H 2), whereby the plurality of first surgical fasteners is configured to apply a first compressive force (F A)to tissue upon formation of the plurality of the first surgical fasteners, and the plurality of second surgical fasteners is configured to apply a second compressive force (F B) to tissue upon formation of the plurality of the second surgical fasteners; characterised in that the first height (H 1) and the second height (H 2) are different, and the first compressive force (F A) and the second compressive force (F B) are different. a first jaw including a cartridge body housing a plurality of first and second surgical fasteners (130, 130 A, 130B); and a second jaw connected to the first jaw such that the first and second jaws are repositionable between unapproximated and approximated positions, the second jaw including a tissue contacting surface having a plurality of fastener forming pockets formed therein, each of the plurality of fastener forming pockets being configured and dimensioned to receive and effect the formation of the plurality of first and second surgical fasteners upon ejection from the cartridge body; wherein the plurality of surgical fasteners include: a plurality of first surgical fasteners, each of the plurality of first surgical fasteners having a first pair of legs terminating in penetrating ends, the first pair of legs being connected by a first backspan having a hump extending towards the penetrating ends, the hump defining a first height (H 1); and a plurality of second surgical fasteners, each of the plurality of second surgical fasteners having a second pair of legs terminating in penetrating ends, the second pair of legs being connected by a second backspan having a hump extending towards the penetrating ends, the hump defining a second height (H 2), whereby the plurality of first surgical fasteners is configured to apply a first compressive force (F A)to tissue upon formation of the plurality of the first surgical fasteners, and the plurality of second surgical fasteners is configured to apply a second compressive force (F B) to tissue upon formation of the plurality of the second surgical fasteners; characterised in that the first height (H 1) and the second height (H 2) are different, and the first compressive force (F A) and the second compressive force (F B) are different. a plurality of first surgical fasteners, each of the plurality of first surgical fasteners having a first pair of legs terminating in penetrating ends, the first pair of legs being connected by a first backspan having a hump extending towards the penetrating ends, the hump defining a first height (H 1); and a plurality of second surgical fasteners, each of the plurality of second surgical fasteners having a second pair of legs terminating in penetrating ends, the second pair of legs being connected by a second backspan having a hump extending towards the penetrating ends, the hump defining a second height (H 2), whereby the plurality of first surgical fasteners is configured to apply a first compressive force (F A)to tissue upon formation of the plurality of the first surgical fasteners, and the plurality of second surgical fasteners is configured to apply a second compressive force (F B) to tissue upon formation of the plurality of the second surgical fasteners; characterised in that the first height (H 1) and the second height (H 2) are different, and the first compressive force (F A) and the second compressive force (F B) are different.