Padlocks are so revered for their efficiency because their design is so incredibly simple. They come in a variety of designs to fit a multitude of purposes. For example, weatherproof padlocks are traditionally made of rust-proof or corrosion-resistant metals like aluminium, brass, or copper so that you can leave them out in the weather without worrying about oxidation and compromised security.
High-security padlocks are usually made of reinforced titanium or steel so that the only way to get through them is with the proper authorization. Combination padlocks require a numeric combination to access, making them resistant to lockpicks. There are all sorts of varieties, making padlocks ideal for numerous security situations.