GG Rubber caps for 'Granton' glockenspiels only.
The usual bottom note of a 'Granton' glock is B, (but may be G) and there is a sliding lever on the front to operate a damper bar. A chromatic glock starting on B requires 42 caps; a chromatic glock starting on G requires 50. A diatonic glock starting on B requires 26 caps. Sold singly.
See here for lengths of rubber for 'Granton' glockenspiels