Just thought I would pass this information along. I installed one of these pinch valves http://www.usplastic.com/catalog/item.aspx?itemid=29062 yesterday in place of a ball valve. So far it looks to be as good as a needle valve for a heck of a lot less money. The 3/8" size is less than $10. Since it slips over the tube there are no connections to leak. I get as good of control over the flow as I did with $50 needle valve that started leaking.