I bought a rattle box last year. It's not quite as convenient to carry as a bag but it sounds great. I rattled in and arrowed a mature 9 pointer on November 8th this year.
www.bmoproducts.com
www.bmoproducts.com
I use the real thing. I use a small bungy cord wrapped around them to keep them from clanging around while walking in. I strap them on the front of backpack with ease. Much funner and more realistic sound. When i rattle i hit and grind em so hard i can smell burning bone. Only downfall is they are very visible which i usually turn away from the buck im calling to hide the horns movement.