Patent claim: The fastener cartridge assembly of any preceding Claim wherein the first compensation layer comprises a first material selected from a group comprising polymeric material biological material and electrical material and wherein the second compensation layer comprises a second material selected from a group comprising polymeric material biological material and electrical material.

Related passage: Although the first layer 1011 can be compressible the second layer 1012 can be substantially more compressible than the first layer 1011.For example the second layer 1012can be about twice as compressible about three times as compressible about four times as compressible about five times as compressible andor about ten times as compressible for example as the first layer 1011.Stated another way the second layer 1012 may compress about two times about three times about four times about five times andor about ten times as much as first layer 1011 for a given force.In certain embodiments the second layer 1012 can be between about twice as compressible and about ten times as compressible for example as the first layer 1011.In at least one embodiment the second layer 1012 can comprise a plurality of air voids defined therein wherein the amount andor size of the air voids in the second layer 1012 can be controlled in order to provide a desired compressibility of the second layer 1012.Similar to the above although the third layer 1013 can be compressible the fourth layer 1014 can be substantially more compressible than the third layer 1013.For example the fourth layer 1014 can be about twice as compressible about three times as compressible about four times as compressible about five times as compressible andor about ten times as compressible for example as the third layer 1013.Stated another way the fourth layer 1014 may compress about two times about three times about four times about five times andor about ten times as much as third layer 1013 for a given force.In certain embodiments the fourth layer 1014 can be between about twice as compressible and about ten times as compressible for example as the third layer 1013.In at least one embodiment the fourth layer 1014 can comprise a plurality of air voids defined therein wherein the amount andor size of the air voids in the fourth layer 1014 can be controlled in order to provide a desired compressibility of the fourth layer 1014.In various circumstances the compressibility of a cartridge body or cartridge body layer can be expressed in terms of a compression rate i.e.a distance in which a layer is compressed for a given amount of force.For example a layer having a high compression rate will compress a larger distance for a given amount of compressive force applied to the layer as compared to a layer having a lower compression rate.This being said the second layer 1012 can have a higher compression rate than the first layer 1011 and similarly the fourth layer 1014 can have a higher compression rate than the third layer 1013.In various embodiments the second layer 1012 and the fourth layer 1014 can be comprised of the same material and can comprise the same compression rate.In various embodiments the second layer 1012 and the fourth layer 1014 can be comprised of materials having different compression rates.Similarly the first layer 1011 and the third layer 1013 can be comprised of the same material and can comprise the samecompression rate.In certain embodiments the first layer 1011 and the third layer 1013 can be comprised of materials having different compression rates.