540ml jars made of glass for preserves. These 540 ml jars are made of high-quality glass. The thick glass allows for safer storage of products, without worry of breakage during the canning process. These jars are resistant to high temperatures and do not absorb odors, allowing for repeated sterilization and boiling. Ideal for pickling cucumbers, marinating mushrooms, and making sweet jams. With their optimal size, they can also be used as glass containers for lunch at work.