No jacket is too tight for our 1.5 mil round bottom antistatic inner. 1950s Columbia jackets, dowel sleeves, even the heavy paper sleeves inside modern LP reissues--these sleeves will fit them all. They are made from the same antistatic HDPE as our other inners, but slightly thinner to help them squeeze into spaces where the others cannot. Every sleeve is precision die-cut for a perfect fit. Never again will you have to choose between a modern antistatic sleeve and your record's original--with these you can have both. Measurements: 12 1/8" x 12 1/8".