No Returns of Non-Defective Products.  All Sales are Final. We do not accept returns of non-defective merchandise.  All tubes are guaranteed against failure for thirty days from shipping date. We do not guarantee tubes against electrical or mechanical abuse, breakage, microphonicity, "noise", failure to meet testing/matching standards on any equipment other than our own or any other conditions we decide are outside the scope of our limited warranty. Please return tube for replacement, if a tube fails in normal service excluding abuse. Customers are responsible for all shipping charges.