Hello, Do not open the small diameter (less than 6cm). The jars with the lid too close either glass flange (the jaws do not go to be able to lift). The covers can not be reused after opening (deep deformation). Good price but I still prefer the rotar
It is the second that I buy and this one is as a gift to a friend. This will tell you how much I was pleased with the first. This device really opens all the jars of all dimensions and without any difficulty. So I highly recommend.