We have used a 'sonic' attachment to a standard grease gun. This has been a very productive tool for us. It is a quick way to check bearings without the need of taking and analyizing all of the vibration data. Also, when you spot a problem the sonic grease gun helps you to put in the correct amount of grease. The use of the sonic grease gun works will in tandem with our vibration analysis. Each calls on the other to verify findings or to aid in the troubleshooting analyis. The downside is that it is user specific. Not everyone could pick it up, listen to a bearing, and have the same analyis. It definitely takes some use before a person understands what he is listening to and can act appropriately. It took less than a month for our primary user to become proficient.