4 7/16″ high x 2 3/4″ wide x 1 7/16″ deep x 5/8″ shackle diameter. Lock case made with unique process of sintering powdered metal and then chrome plating it. Cylinder mechanism loaded from the top. This design inherently makes removing the cylinder from the bottom of the lock very difficult. Originally designed as a railroad switch lock except that this model has 5 high security disk tumblers instead of the 3 that are installed in the railroad switch lock model.Patent # 4359886.