"Cursitor Doom" wrote in message
...
On Sun, 20 Jan 2019 14:20:22 +1100, FMurtz wrote:

But this one breaks the seal by pressure on opposite sides of the lid
and then takes little effort.

ISTR that pre 1991 when we had that epidemic of food tampering and the
jars were at that time not vacuum sealed, there were *still* some lids
that were a serious PITA to off. So it has do more than just releasing
the vacuum.

No it does not and the fact that one of these works
every time unless the lid is too deep proves that.
https://www.amazon.co.uk/gpo/product...e=UTF8&ps c=1