Golf club head with open back cavity

A golf club head comprises a hollow body comprising a front opening (7128, fig 53) covered by a faceplate 7108 defining a strike face 7112, a heel region, a toe region opposite the heel region, a sole 7122 and a top rail 7124; a back wall 7132 opposite the strikeface 7112, wherein the back wall 7132 is divided into an upper back wall 7134 and a lower back wall 7136; the back wall also including an upper indentation wall 7142, top cavity wall 7138, bottom cavity wall 7140 and lower indentation wall 7144 that define a rear opening 7104 communicating with a cavity 7102. A rear opening rim including an upper rim 7150 and lower rim 7152 circumscribes the rear opening 7104. A midplane 7184 extends through the geometric centre of the strikeface 7112 and the rear opening 7104 is located between the midplane 7184 and the top rail 7124. The sole 7122 includes a thinned region and a cavity in the club head includes top and bottom channels. A badge 7114 may at least partially cover the rear opening 7104.