Putter-type golf club head

A putter-type golf club head, comprising:

• a body portion, comprising:
• a ball-striking surface, a top surface, and a rear surface, wherein the ball-striking surface is opposite to the rear surface, the top surface connects the ball-striking surface and the rear surface, the top surface is provided with an opening of the top surface, and the rear surface is provided with an opening of the rear surface;
• an extension portion disposed on the rear surface of the body portion, the extension portion comprising:
• a first frame, a second frame, a rear frame, and an intermediate frame, and wherein the first frame, the second frame, the rear frame, and the intermediate frame are respectively provided with at least one opening;
• a shaft adapter movably disposed in the opening of the top surface or the opening of the extension portion;
• and
• a shaft fastener member configured to pass through the opening of the rear surface or the opening of the extension portion to fix the shaft adapter.