Crosstac Tactical Rear Squeeze Bag Prefilled Zippered rather than stitched so you can get into the bag and adjust the fill Density and type. Want a lower bag Remove some fill. Want it firmer add some fill. Simple and effective Oval shape ergonomically fits your hand, very comfortable for extended Shooting periods. Size is 6.0" or 8.0" long with a 4.0" x 2.5" Oval shape Unique one-way stretch feature. The Special fabric only stretches vertically - this means when you squeeze the bag, the pressure causes the bag to Go up, doing what you want, rather than out Mil-Spec coated fabric has a Super tough rubberized "Grippe" exterior