Pioneer 12 Inch by 12 Inch and 8 1/2 Inch by 11 Inch Memory Book Spacers Fits 12 inch by 12 inch and 8 1/2 inch by 11 inch post bound and strap style memory books Perforations let you size down for 8 1/2 inch x 11 inch post bound and strap style memory books 12 spacers per package Adds additional strength to the book spine Archival and photo safe: acid, lignin and PVC free