Whether a beginning lock picker or a veteran locksmith, everyone needs practice, and the Brockhage Clear Standard Pin Practice Lock is a great way to learn and hone your skills. With its transparent shell, this easy to use practice lock allows you to see the inner workings of a standard pin lock and, thus, develop a greater understanding of its operation. It also affords a chance at trial-and-error with no problematic consequences, before attempting to tackle the genuine article. Includes two master keys. Measures 3 4/5” x 2 2/5”.