I use the REI Flash pack, Light weight and pretty cheaply priced. Holds my rack, harness and strapped to the daisy's, shoes and helmet for near car climbing. For longer treks it is light enough and fully compressible so it fits great in a bigger pack. Ice season sees it as a stuff sack for my down coat, extra gloves and water. Originally bought it for the wife to use as a light day hiking pack, but she has yet to be able to pry it from my back.