SAE8655 chrome molybdenum steel used for the face
with 3-level thickness deviation

SAE8655 chrome molybdenum steel tougher than soft iron is used for the face. The creation of excess weight and a deeper, lower center of gravity, results in the ball rising easily and straight ball flight.

Featuring a 3-level thickness deviation with three different phases of thickness.
In order to eliminate the unsatisfying feel and sound of face-welded irons, the lower area of the face is made thicker to 2.7mm and the top blade thinner so that even players with slower head speeds can feel good ball retention.

Only the upper part of the face was processed with high-frequency heat treatment to increase the rigidity, successfully creating strength that can withstand with the 1.8mm thinness.

Engineered with optimal weight placement in pursuit of results

The bold pocket cavity structure and face with thickness deviation result in a low and deep center of gravity. This led to the mis-hit forgiveness and straight ball flight performance that PROTO-CONCEPT delivers.

While adopting an orthodox shape that satisfies feel such as ease of addressing and swinging, the face with proprietary 3-level thickness deviation, and the body is made of soft S20C material to achieve high bounce, solid feel and ball retention.