These heavy gauge cores have a .060 wall thickness and an inside diameter of 1.02 inches, which allows a one inch dowel to slide through.  Overall length of these tubes are 36 inches.  They are too thick to cut with a razor knife, but there are several types of saws which work wonderful for cutting them to any size.  Our favorite cutting method is with a band knife blade.  Customers also tell us that fine tooth band saw and hack saw blades work good if you have both time and patience.  People who have purchased these have used them for everything from fireworks construction, tube club events, arts and crafts, for mailing items in a secure enclosure, and for storing oversize drawings or posters.  Please email your questions.  Worldwide shipping available on everything we sell.