Fees start at $150 for US trademark applications and registrations for a simple single word or letter combination mark. A preliminary search, also known as a screening or knock-out search, will identify obvious issues in registering the proposed mark; e.g. it will identify prior identical marks that would prevent the registration of the proposed mark. A preliminary search is limited to a review of resources most likely to yield relevant marks with a minimum of search strategies. A preliminary search will eliminate or "knock-out" proposed marks that are clearly unavailable. In this respect, the preliminary research avoids the time and expense of a full trademark search. However, aside from a knock-out hit, a preliminary search alone will not be determinative of whether the proposed mark is available for use.