Replacement canning jar wide mouth lid. Replace those old metal lids with our soft plastic with moisture chamber and digital hygrometer cap. Easy way to burp you jars during curing and drying of your home grow Cannabis. Always monitor your humidity levels to keep your Cannabis at its optimal level of 62% RH. Great storage space to hold your favorite humidity control packs or Cannisters. Comes with lid, digital hygrometer, battery, new replacement metal ring, stickers and instructions on how to use.