The Fiskars Extra Plates are perfect in every way. Same size, same thickness as far as I could tell. I'd recommend this product for anyone who is an avid stamper - or not.
These are meant to be used as a storage system for great acrylic block ideas that you will use again. They fit in the Stamp Press and work perfect! But - I use them a little different. They are my large acrylic blocks! They fit the extra large stamps like Fancy Pants and the cost is affordable! You get 2 plates in a pack for under $10! They are a little harder to handle but it is so worth it!