These weights are actually Weck reusable Glass Lids.  Made of the highest quality glass, they contain NO BPA! (Bisphenol A), lead, mercury or cadmium.
 
 Weck glass jar lids are the only preserving lids in the world that can be reused thousands of times and the only glass certified as lead free.
 
Lids come in 3 sizes: small, medium and large.  Small = 70mm, Medium = 90mm, Large = 110mm.
 
If you are using one of our Weck Rex fermenting jars, choose small for the 1 litre jars and the 1.5 litre jars.
 
For the Ball 2 litre jars and Fido jars you can use the small weight but due to the width of the shoulders there will not be a full coverage of the surface. 

In this instance you can use leaves such as cabbage leaves to cover the surface and then weight this with the small weight.
 
Note that the fit is tight and if you are fermenting very liquid foods, the weight will sink unless there is sufficient food mass in the jar to hold it up. 

You can also place a piece of cabbage leaf over the top of your ferment and then place the weight on top to ensure the entire surface is submerged.
 
Small approx 50g
 
Medium approx 85g