What size and shape padlock should I choose? The size and shape of a padlock is not just a question of looks; it’s about choosing the best lock for your purpose. What’s the right size padlock body? When it comes to padlocks size does not necessarily equate with strength. For instance a large, chunky padlock made from cheap materials will be much easier to break than a smaller, hardened steel version with a protected shackle. The size of your padlock should therefore be determined by the available space and the type of item being secured (hasp, chain links, bar etc). Yale's full range padlocks with different sizes What’s the right body shape? Padlocks fall into four broad categories, or shapes, that lend themselves to different purposes. Conventional padlocks come in a variety of padlock materials and padlock shackle types making them suitable for a wide range of uses from low-security applications like locking toolboxes, to high-security uses like securing factory gates or protecting motorcycles. Disc padlocks are generally round with a small, exposed shackle. Because there are no corners they are a good choice for securing chains and cables, for instance when locking up a bike. They are also often used on doors exposed to weather, such as sheds and beach houses. A discus hasp and staple set provides even greater protection against attack. Shutter / Straight shackle padlocks use a straight, rather than hooked, shackle making them compact with a low profile and highly resistant to attack. They are typically used on security roller shutters fitted to shop fronts and with parking posts and motorcycle security chains. Shackleless / closed shackle padlocks do have a shackle but it is “hidden” on the underside of the lock body, making them very attack resistant. They can be round or rectangular and are designed to be used with a matching security hasp. They are popular for securing double doors like those used on warehouses and vans.