Become the top-secret agent you always wanted to be with this novelty item. If you haven’t gotten a comb knife yet, you need to get familiar. These are the hottest gifts around. Get blue and red for a guy to use as a cool conversation piece. or get the pink and purple for the girl that has everything. A simple, harmless comb at first sight, this covert piece transforms into a useful knife measuring almost 7 inches in length. The blade is 3.5 inches and features half-serration for any task. It is also the perfect product to buy for beginners or anyone who is not familiar with knives.