Each piece of Pyrex is marked on the bottom. You should easily find the size. New pieces made in the seventies are marked for use in a microwave.

When purchasing any piece on EBay always remember condition, condition condition! A damaged piece is not decorative, durable nor will it have a long life. Read the description very carefully, is it in a box, is it in mint condition? Does the design show ware or is the color faded? Has the seller listed the size carefully? Do they describe the mark on the bottom? What is the size? Are they knowledgeable about the pattern name? Is the piece clean? Do they guarantee that the real Pyrex, not Glass Bake or another glassware product? Does it have a chips, crack or fleabite on either the piece or lid? Do they include the lid?

If the seller does not list the information you need, contact them. See what type of sellers they are. Are they responsive to your questions? After over 1,800 transactions on EBay I have found if they don’t respond to your questions before the sale in a curious way, they surely will not answer your questions after the sale if you have an issue.

Guide 4 will inform you on Tips on using Pyrex