Designed For Mason Jar Fermentation Pickle Pebbles are specifically designed for mason jar fermentation and take the guesswork out of your lacto fermentation by ensuring your veggies stay below the surface of the brine thereby eliminating exposure to oxygen (which is the main cause of failure when using lacto fermentation methods).Pickle Pebbles are designed for mason jars but can also be used in other types of fermenting vessels such as the Fido style jar, as well as traditional ceramic crocks.Perfect Fit - Thick and Heavy While a single Pickle Pebble is often enough to keep veggies below the brine, they can also be stacked to provide extra weight.Combo Pack includes Pickle Pebbles Plus (7cm diameter with 1.9cm thickness and weighs 180mls (170 grammes)) and Pickle Pebbles Standard (Dimensions: 5.7cm diameter with 1.5cm thickness).Pure Moulded Soda-Lime Glass Pickle Pebbles are made of non-iridized soda glass which is completely inert and guarantees that no other substances leach into your ferment.We make our fermentation weights from the same type of glass as Ball, Kerr and Bernardin mason jar brands.Pickle Pebble is moulded individually, unlike other weights, which are cut from sheets of optical window glass - these products often have a green tint and a frosted cut edge.Each Pickle Pebble PLUS is 5.7cm diameter with 1.5cm thickness.Best-Quality, Independently Tested Pickle Pebble are individually inspected to ensure the highest possible quality.Food-Safety tests performed by SGS North America to ensure Pickle Pebbles meet the highest safety standards.