The DeWALT DWST28001 28 in. Water Seal Tool Box has a water seal to help protect the contents. The structural foam tool box has latches that are made of rust proof metal. This garage accessory has a 100 lbs load capacity with 9.2 gal of useful volume for your convenience. 2. Are toolboxes waterproof? Naturally, all toolboxes are weather-resistant and are made to keep out the rain during your travels. A large portion of them is not built to be truly waterproof. Most storage boxes, especially those on the cheaper end, do not come with an adequate amount of seals to keep out water completely. 3. Is Tstak waterproof? If you are a professional and you need to carry your tools every day at work, you need a larger toolbox which should also be easy for you to carry daily. So, you should make a list of all your tools in the beginning so you get an idea for what exactly you are looking for.