This is a  VINTAGE Pyrex Corning Ware Replacement  10" clear glass lid with a square domed cover. 

It is a casserole lid suitable for a 1970s-1979 production style pressed glass Pyrex Corning Ware A12C model. 

The lid has a flat-bottomed design, is freezer-safe, non-stick, and dishwasher safe.

Made in the USA

It is in excellent condition free from chips or cracks