This is weirdly advertised…
If think this product excels at mitigating dead spots on bass guitars.
I noticed no relevant changes regarding the sustain of the overall bass, but it did help making the dead spot on my Sire V5 (C# on G string) less pronounced. It helps only when placed on the TOP of the headstock (it doesn’t mitigate the dead spot if it’s placed on the side or on the junction with neck. I have no idea why). Overall, a good product that should be better advertised. Although it doesn’t solve the problem 100%, it makes it 50% better, which is a win for me.