These are the *original* design that came in one size; they are not module like the new ones. They’ve been discontinued, to a lot of customers’ dismay, because they fit perfectly in any travel bag. They feature STRONG magnets, which allow them to stay bundled together while traveling and the caps stick to the side of the capsule when unscrewed so it won’t get lost! They claim to be 100% leakproof, although I did have one leak olaplex oil because the product was so thin. Rubber gaskets inside the capsules keep the lids on securely and tight. Each container holds .56 ounces, enough for a 2-3 day getaway. So cute, so convenient and takes up so little space in your carry on. They’re made of recycled plastic and metal, so they are a little heavy. Nothing that ever bothered me. I have two more sets that I use every time I travel. Keep in mind, since the originals have been discontinued, the labels cannot be replaced. These were very expensive, so it’s a good way to introduce yourself to the Cadence line of products! Each container was hand washed with Dawn dish soap and dried by microfiber towel. In nearly new condition. Beautiful periwinkle color. Makes hotel showering so easy! Sold as a set.