the vertical dashed lines or at other desired locations by separating the skirt system 42 at one of the vertical dashed lines illustrated in fig5 the skirt system forms two independent skirt portions in which one skirt portion comprises an independent elastomeric layer skirt portion or alternatively an independent mechanical layer skirt portion use of independent skirt portions 73 provides an ability to crimp specific packer layers without any interaction between those layers during operation of the packer the mechanical layer retention region 66 of inner nipple 38 also may comprise a crimped surface region 74 as illustrated in fig6 the surface region 74 is designed to engage crimped end portion 68 on an opposite side of mechanical layer 52 relative to crimped engagement region 70 consequently the mechanical layer 52 is securely and independently gripped and retained between inner packer nipple 38 and outer skirt 40 retention features 58 also may comprise a variety of other mechanisms and surfaces for example inner bladder gripping region 62 may comprise a series of surface undulations 76 as illustrated in fig6 the surface undulations 76 are designed to sink into and grip the elastomeric material of inner bladder layer 48 when the inner bladder layer is crimped or otherwise secured in mechanical extremity 36 the anti extrusion layer gripping region 64 also may comprise a variety of configurations in the embodiment illustrated in fig6 and 7 the anti extrusion layer gripping region 64 comprises a multilevel surface or profile 78 designed to engage the.