Recrystallized silicon carbide shelves are not all the same
After many years of firing to cone 11.
I had to trade out two Chinese shelves due to near failure.
I bought two a few years ago to test along with my 50 advancers.
These where the Chinese ones with and without the relief cuts in them.
Booth where used as bottom shelves as well as throughout the load.
They have both warped 3/8 of and inch or more as well as cracked. The advancers are as flat and crack free as the day I bought them. These shelves have hundreds of fires on them. So when you think why the Chinese ones cost 1/3 as much its because you will need to replace them many times to equal an advancer.