Besides the fact that the hex base allows for quick replacement, the hex base also ensures this bit works without slipping. Other regular bottom countersinks that I had, slipped even when tightened. The description is missing an important feature: This countersink is 5/8" in diameter. Before ordering, I verified this by contacting Snappy. Like all Snappy Products a very high quality product, 5 stars from me because it works in both wood and metal, does not slip in the chuck, fits keylessβ¦