Medeco M3 5/16" Shrouded Boron Padlock, 3/4'' Shackle Clearance, Indoor/Outdoor Unique elevating and rotating tumbler pin system is virtually pick proof. Hardened stainless steel inserts inside the cylinder provide the ultimate defense against drilling and other forms of physical attack. Comes with 2 keys and a code card. The shrouded shackle design provides extra shackle protection against cutting attacks. Patented Medeco3 keys may only be duplicated by Medeco or an authorized Medeco service outlet, and only at your request.