Bat rolling (a Accelerated Break In Technique) has been around since the early 2000s and up until recently there was no positive way to measure its effects. The Compression tester is a new way to gauge the psi of a bat. The tester comes in 3 types: USSSA Compression Tester, ASA Compression Tester, and a Baseball 2 5/8 Barrel Tester. A bat is placed inside one of these testers and the machine puts pressure on the barrel to measure flex (or psi). A bat that has been rolled is supposed to have more flex than prior to rolling and now we have a way to prove that statement. Every bat we break in now comes with a compression card with before and after results. These results have verified what we had already known; ABI (accelerated Break In) Techniques are absolutely effective and every bat now has that assurance. In the past I would roll a bat and just not have the warm and fuzzy that much composite break down was going on but now with the compression tester I see the results and they are pretty darn beneficial. So the next time you need your bats broken in always get written or verified results it will keep you bat roller in check and give you confidence in the ABI service performed.