An express warranty is a verbal or written statement that guarantees that a product is of a certain quality or will work in a certain way or for a certain amount of time. Most express warranties say something like, "This product is warranted against defects in materials or workmanship" or "We will repair or replace parts that are defective in materials or workmanship" for a specified time.
You are not automatically entitled to an express warranty. Most express warranties either come directly from the manufacturer or are included in the sales contract you sign with the seller. However, an express warranty may also be a feature in an advertisement or on a sign in the store (for example, "all dresses 100% silk"), or it may be an oral description of a product's features that you rely on in making your purchasing decision.