The most durable ProMark Rebound 5AB drumsticks. FireGrain refers to a patented heat treatment process that transforms ordinary hickory sticks into high-precision tools with unprecedented durability. Without compromising weight or balance, ProMark FireGrain sticks naturally allow drummers to hit harder and play longer. No excessive vibrations, no technological gimmicks, just natural hickory hardened by flames. This 5AB model features a diameter of 14.7 mm (.580"), halfway between 5A and 5B sticks.