Plastic Jar 250 ml comes with black cap screw closure with liner PLUS a Pressure-Sensitive Liner for leak prevention. The complete kit includes: 250 ml (8 oz) PET plastic jar Black Cap with Liner (this is separate from the pressure-sensitive liner) Pressure-Sensitive Liner The Pressure-Sensitive Liner provides an air-tight seal after you screw on the cap and helps to prevent leaks. Now you can properly seal all of your cosmetic formulations easily and quickly! For example, you may wish to whip up some body butter and give as gifts to friends and family. Or start up your own micro manufacturing enterprise. PET is an inert type of plastic, the same as used for water bottles. This jar can be re-used many times and then eventually recycled.