on or two chips .90, I pop the bubbles and the mailer will then go thru the guide for 1/4 in. It takes a little time and builds your thumb muscle, but saves a buck a package, I also put the 1 or 2 chips at the end on mailer with tape so they wont move and can bend and go thru a sorter if they choose to do that. Sent hundreds and never had a postage due, or broken chip or chips.