Locking Mason jars with hermetic lids seal in garden freshness. Locking glass Mason jars seal in garden freshness. Hermetic lids with rubber clamp and sure-grip clamp creates an airtight seal. Excellent preserving jars for canning vegetables or fruit. Ideal storage for dry ingredients on pantry shelves or homemade salsas, dips or dressings in the fridge. Vintage-style jars reinvent the traditional method of canning to preserve flavors the natural way