I own a Robart 411 hobby paint shaker that I use to shake bottles after steeping in a heating pad (low setting 105 degrees) for a few hours. I was searching for one that did multiple bottles that I could get cheap but found nothing in my price range. I did however find the below linked product. I might have to buy one when it comes out later this month and be able to shake 2 bottles at once until my Robart gives out.