US Patent 9440123 Golf club head with accessible interior

The invention provides a golf club head having a port for providing a view into the interior cavity of the club head. The club head further includes at least one rib positioned along an internal surface of the club head and adjacent to the port. The at least one rib is configured to provide sound tuning characteristics, increasing the frequency of the port, thereby improving acoustic properties of the club head, particularly the sound produced by the golf club head during ball impact.