Small batch fermentation kit has everything you need to get started - just add your own veggies or fruit! Kit includes glass storage mason jar, stainless steel top does not react with salt or acid and will not rust. It's a weight:The press and spring load keeps vegetables submerged below the brine, and will not fall into the jar or break. It's an airlock: Keeps air out and allows for CO2 to safely escape. Dishwasher safe.