Dan I have used mine up to 12" deep with little problems. I definitely don't get the vibration from it like I do the 1/2". Like Vaughn said it is really handy around the shoulders and I to don't use it all the time but when needed it sure does come in handy. I can say I wouldn't want to be without it and glad I did buy it.
Retirement: That’s when you return from work one day
and say, “Hi, Honey, I’m home – forever.”
To succeed in life, you need three things: a wishbone, a backbone and a funnybone.