NcStar has one of the most consumer friendly warranties on the market!
Here is an excerpt from their warranty page. For full warranty information click the link. Warranty Information
Our 90 Day Guarantee: If you purchased your product within the last 90 days then we will waive the $10.00 handling fee. All you have to include with your letter is a copy of your receipt or proof of purchase. All NcSTAR optical products carry a Limited Lifetime Warranty. All other NcSTAR Products carry a Limited One Year Warranty.