Here is a foldable weight that you can use anywhere to push your body hard. The Exerbell has a minimalist design and lets you train with water to add instability to your exercises. You can also fill it with sand when you are near the beach for more weight. Weight markings are available inside, so you can easily adjust the weight from 2kg to 14kg.
The Exerbell has a soft, leak-proof construction. Its shell is made of recycled PET. You can find out more about it here.