The smokey grey-coloured coating makes this preserving jar particularly decorative. That is why they are not only the right choice as jam jars, but also as storage jars or for DIY projects outside the kitchen. Of course, the jars can be sealed airtight. The aluminum lid can be labeled and uses the finger test to indicate whether the jars are properly closed. If this does not give in to pressure with the finger, a vacuum is created. This also prevents mold from developing. The jars can be filled with contents up to 100°C. That's why they're perfect for canning. They are not suitable for preserving or fatty foods. Dishwasher safe.