I always used the NHL Fox40 whistle since I started officiating 15 years ago. I decided to give the ACME whistle a shot as I know all of my fellow friends/colleagues in the AHL/NHL opt in for this whistle. I was NOT disappointed! The whistle has a louder-pitched chirp when you blow into it, and I find that it has a better impact on game management, as it provides a slightly unique sound compared to other sounds typically found in arenas where players can more easily differentiate between the two. It also came with a rubberized piece that covers the upper half of the whistle, including the portion of the whistle that typically goes in the mouth. The rubberized piece is optional and can be easily added or removed based on discretion. Personally, I prefer to have it on the whistle as it makes for easier cleaning of the whistle. Prior to that, I used to wrap tape around that portion. Additionally, I think it's a more effective option than tape when it comes to not cracking your teeth on the whistle when you're bringing it to your mouth, and lets face it... there are only two types of officials. Those who have clipped their teeth once or twice already and those who are going to clip their teeth once or twice in their career. I recommend this product over the NHL Fox40 whistle.