28 that extends beyond straps 24 b f closer to second side edge 20 device 10 includes a longitudinally extending strap 30 that extends upwardly from bottom edge 16 and traverses each laterally extending strap 22 the top end of longitudinally extending strap 30 extends beyond top edge 14 two d rings 32 are secured to the top end of longitudinal strap 30 and two d rings 33 are secured to the bottom end of longitudinal strap 30 longitudinally extending strap 30 is parallel to and laterally offset from first side edge 18 in one or more embodiments longitudinally extending strap 30 is offset from first side edge 18 by about u2159 the total lateral width of cover 12 a second longitudinally extending strap 34 also runs parallel to first side edge 18 and is offset therefrom in one or more embodiments second longitudinally extending strap 34 is offset by about u00bd the total lateral width of cover 12 second longitudinally extending strap 34 is secured to cover 12 from a point proximate to bottom edge 16 to a point approximately half way between bottom edge 16 and top edge 14 in one embodiment second longitudinal strap 34 is secured to lateral straps 22 d f and to the portions of cover 12 therebetween a top portion 36 of second lontigudinally extending strap 34 is not secured to either cover 12 or lateral strap 22 likewise a bottom portion 38 of second longitudinally extending strap 34 is not secured to either cover 12 or lateral strap 22 and extends beyond bottom edge 16 as seen in fig2 bottom portion 38 is substantially longer than top portion 36 device 10 includes a third.