In putting, the ball doesn't roll immediately but creates unstable movement, as shown in the picture in the 15-18% of the initial section of the total distance traveled. This will create distortions in the 'direction and distance' of the ball. The hitting-type putting creates natural movement as the ball rolls on the ground. However, if you hit the ball, it creates distortion where it doesn't roll immediately and skids. In this case, you may find it difficult to produce consistent putting results, which will make it hard to putt.

The USGA decided to use the stimpmeter with zero distortion as the standard green speed measuring device when they found it difficult to utilize the putter with its limitations in terms of consistency. To roll the ball accurately on the ground, it's better to apply a rolling-type method rather than a pushing or hitting-type method. That's why the stimpmeter (USGA's approved standard measuring device) measures the distance by rolling-type rather than hitting-type to obtain the standard value of its measurement. In other words, the existing hitting method makes it difficult to produce a consistent value due to distortion in the initial skidding section. In the end, the ideal putter creates a natural rotation of the ball immediately after hitting and minimizes distortion where the ball skids.

The best putters rotate immediately at impact. It helps the ball to generate a forward rotation directly along the ground by minimizing the initial skidding section.

PISA focused on the putter's loft to generate a forward rotation immediately at impact. Through several tests, we concluded that a negative loft is an answer to its problem since the existing positive loft can't create a forward rotation at impact. In addition, we developed a technology to overcome or reversely use the rotational friction, which is considered the biggest disadvantage of the negative loft. The negative loft on the putter, low-friction materials, and a linear bearing module do not interrupt the ball's rotation. Furthermore, it is considered a technology that actively creates the spin corresponding to the amount of impact on the ball by increasing the impact surface. Such technology has proven its effectiveness, and we will gradually improve its performance.