This quality kiln shelf is made of durable ceramic and will last through years of normal use. Some of my customers dip these in glass separator and cure before use. I think that's a great idea. This shelf is great for smaller kilns. Just make sure to measure your kiln before ordering.
These are cut from large slabs before they get to me and sometimes have some edge chipping or minor variations in size which will not diminish performance.
Rated to 2300 degrees.