The AML20036 Lock Cylinder Model 5-Piece Set + AML20189 Transparent Practice Cross Lock will help you quickly learn how to pick common residential cross locks. The practice cross lock is made of transparent material so you can see how the internal components work inside the lock while you are working on it. Such a great tool is sure to make it easier to learn lock picking and improve your lock-picking skills significantly. Plus， a set of five lock cylinder models are great for training and testing your learned skills. Don’t miss out!                                    Features             Help you quickly learn how to pick common residential cross locks<br> The practice cross lock has a transparent construction<br> Let you see how the internal components work inside the lock<br> A set of five lock cylinder models are great for training and testing your learned skills<br> High quality， tough and durable <br>                                                            Specifications             Lock Material     Copper & Crystal    <br> Lock Dimensions     (4.84 x 1.84)" / (12.3 x 3.4)cm (L x Dia.)    <br> Lock Color     Lucency    <br> Key Color     Blue    <br> Weight     3.88oz / 110g       <br>                                                             Package Includes            1 x Cow Practise Transparent Lock Cross Lock<br>1 x Cross Mould Key Lock Core<br>