Created to be nearly the same size as the rubber spring mute that comes standard on Ibanez AZ series guitars. *Because these are handmade, there may be some size variations. The third photo is an image of the original part that comes with the AZ. This has the effect of suppressing the resonance/vibration of the springs. Soft-type springs like Raw Vintage can sometimes produce too much reverb, but using this will help to moderately suppress the sound. This is a set of 5, so you can adjust the number of springs used to change the sound. The original part is made of rubber, but this is made of silicone, considering aging and deterioration. Ships via mini-letter. 2TRX5BA010 2TRX5BA011