An ultrasonic sealing device, comprising: a horn (112, 512) having a sealing surface; an anvil (114, 514) having a sealing surface, at least one of said horn (112, 512) and said anvil (114, 514) being moveable to engage the sealing surface of said horn (112, 512) with the sealing surface of said anvil (114, 514); the sealing surfaces of each of said horn (112, 512) and said anvil (114, 514) including a plurality of protrusions (302, 602, 604) and a recess between each pair of the protrusions (302, 602, 604), each of the protrusions (302, 602, 604) having distal surface and sidewalls with curved edges therebetween and each of the recesses including a recess surface with curved edges; wherein, upon engagement of the sealing surface of said horn (112, 512) with the sealing surface of said anvil (114, 514), the distal surfaces of each of the protrusions (302, 602, 604) on each of the sealing surfaces engage corresponding ones of the recess surfaces of each of the recesses on each of the sealing surfaces and define a plurality of melt initiation points with gaps (330, 630) between the sidewalls of each adjacent protrusion; and wherein a first subset of the plurality of melt initiation points lie in a first plane and a second subset of the plurality of melt initiation points lie in a second plane parallel to the first plane, such that the plurality of melt initiation points lie in the two parallel planes, characterized in that each of the protrusions on said horn (112, 512), each of the protrusions on said anvil (114, 514), each of the recesses in said horn (112, 512) and each of the recesses in said anvil (114, 514) has a radius of curvature between 787,4 μm (0.031 inches) and 1397 μm (0.055 inches). a horn (112, 512) having a sealing surface; an anvil (114, 514) having a sealing surface, at least one of said horn (112, 512) and said anvil (114, 514) being moveable to engage the sealing surface of said horn (112, 512) with the sealing surface of said anvil (114, 514); the sealing surfaces of each of said horn (112, 512) and said anvil (114, 514) including a plurality of protrusions (302, 602, 604) and a recess between each pair of the protrusions (302, 602, 604), each of the protrusions (302, 602, 604) having distal surface and sidewalls with curved edges therebetween and each of the recesses including a recess surface with curved edges; wherein, upon engagement of the sealing surface of said horn (112, 512) with the sealing surface of said anvil (114, 514), the distal surfaces of each of the protrusions (302, 602, 604) on each of the sealing surfaces engage corresponding ones of the recess surfaces of each of the recesses on each of the sealing surfaces and define a plurality of melt initiation points with gaps (330, 630) between the sidewalls of each adjacent protrusion; and wherein a first subset of the plurality of melt initiation points lie in a first plane and a second subset of the plurality of melt initiation points lie in a second plane parallel to the first plane, such that the plurality of melt initiation points lie in the two parallel planes, characterized in that each of the protrusions on said horn (112, 512), each of the protrusions on said anvil (114, 514), each of the recesses in said horn (112, 512) and each of the recesses in said anvil (114, 514) has a radius of curvature between 787,4 μm (0.031 inches) and 1397 μm (0.055 inches).