资料：When a consumer finds that an item she or he bought is faulty or in some other way does not live up to the manufacturer's claims， the first step is to present the warranty， or any other records which might help. at the store of purchase. In most cases，this action will produce results. However， if it does not， there are various means the consumer may use to gain satisfaction A simple and common method used by many consumers is to complain directly to the store manager. In general， the “higher up” his or her complaint， the faster he or she can expect it to be settled. In such a case， it is usually settled in the consumer's favor， assuming he or she has a just claim.

Consumers should complain in person whenever possible， but if they cannot get to the place of purchase， it is acceptable to phone or write the complaint in a letter.

Complaining is usually most effective when it is done politely but firmly， and especially when the consumer can demonstrate what is wrong with the item in question If this cannot be done， the consumer will succeed best by presenting specific information as to what is wrong. rather than by making general statements. For example，“The left speaker does not work at all and the sound coming out of the right one is unclear” is better than “This stereo does not work” The store manager may advice the consumer to write to the manufacturer. If so， the consumer should do this， stating the complaint as politely and firmly as possible. If a polite complaint does not achieve the desired result， the consumer can go to a step further. She or he can threaten to take the seller to court or report the seller to a private or public organization responsible for protecting consumer's rights.

Why does the author mention the example of stereo in paragraph 3?