Select good confidentiality. The lock that basically chooses key tooth flower to have more, tooth flower is more, the lock that tooth flower discretion changes bigger is opened each other rate is lower.
Pick flexible performance. Insert or remove the key, look at the smooth is not smooth, switch a few times, look at the twist is not hard, not smooth, not save effort flexibility is not good.
Pick firm performance is good. See the variety that locks use material and ply, for example door lock USES the high grade steel plate of 12 silk meters, and some use the common steel plate of 8 silk meters only, the firmness of latter apparently poor much, the length that sees lock tongue even, ply and width, these dimensions are bigger, firmness is taller. The easiest method is the lock of congener is weighed in hand weigh in hand, general component is heavy firm degree is good.
Look for good looks. Check the appearance of the lock, good plating gloss, smooth, flat, no discomfort is good.