It's a proven fact – putting can have the greatest impact on your game. The Clockworx Putting Hole Slope Indicator (HSI) is a unique training device designed to help you gain an advantage on the green. Once you begin training with the Clockworx Putting HSI and Precision Practice system, you will be able to accurately identify the high side, low side and slope of every hole. This will give you the know-how to properly set up putts and master the art of reading the green. The key feature of the Clockworx Putting™ HSI is a circular bubble level indicating the degree of slope (an inclinometer). It's embedded into a holder that rests in and around the rim of the hole – on any regulation green. In the center of the HSI are "crosshair" markings and circles identifying the degrees of slope based on position of the bubble. For example, if the bubble is in the center, there is a 0 degree of slope – the putting surface is perfectly flat. If the bubble comes to rest at the 2-degree circle, then there is a 2-degree slope. Outside of the center are markings to help you clearly identify and mark the key positions of the hole. Simply follow the easy Precision Practice System and you're ready to begin improving your putting! HSI Product Features: · Accurate · Easy to use · Durable · Water proof · Carry in golf bag or pocket .