These sturdy, well-made jars are suited to a wide range of canning tasks, and many people think that they look rather nice as well, making them very popular among cooks all over the world. Good Le Parfait jars can get costly, but some people feel that it is worth the expense, as these jars are known for being extremely reliable and very easy to use. Le Parfait jars really are perfect for a lot of things, thanks to their design. A classic Le Parfait jar has a lid mounted on a wire hinge, with a locking lever to fasten the lid to the top of the jar. A rubber o-ring is inserted into the lid as a gasket, creating an airtight seal inside the jar which will hold until the lever is lifted, breaking the seal. It is also possible to find Le Parfait jars with screw-on caps. For canning, these jars are extremely useful. and because they are clear, it is easy to see the contents of the jar. They can also be used for more general kitchen storage; until cooks are ready to use the contents of the jar, and they can be easily re-sealed. You can also use Le Parfait jars for freezing, although you should be careful to leave a gap at the top of the jar to allow the contents to expand. If the jar lacks sufficient expansion room, it will explode when the contents freeze all the way, since the seal is too strong to allow the jar to simply pop open. Some people also use Le Parfait jars with special ?burping? gaskets to make fermented foods; in this case, the gasket allows gas to escape from the jar, but not to enter it. The basic design of Le Parfait jars may not be terribly innovative or remarkable, but it has become associated with quality, both because the jars are often of very good quality and because they have become popular with gourmets around the world. Many kitchen supply stores sell Le Parfait jars, and you can also order them from companies which specialize in imported French kitchen supplies.