im wondering right now if my ears just suck. hahaha.
basically, in theory, i could take any metalic object and clamp it to the headstock of one of my ukes and get the same effect. so i did.
i used a 10" long metal file and an all metal pocket knife and clamped them to the uke with a capo. each weighs somewhere between 2-4oz (lotta experience with lead fishing sinkers so im not bad at hand-weighing). i tested out their connection with the instrument by using my chromatic tuner. clamped it to the object instead of the wood. good to go.
tried it on my kala (where i was expecting to see the most dramatic change) and on my leolani. i did not notice any difference in the kala, other than the extra weight at the head. the leolani actually developed a twang and lost its warmth. sustain on either uke was not affected.
ok so i realize my experimentation has a lot of variables that could lead to less than desirable results not expected from a small solid metal object designed to be used on an instrument and take up as little space as possible, compared to a 10" long scored strip of metal, and a 4" (when closed) metalic object consisting of spaces, hinge, and several pieces within the unit.
BUT, if the "added mass" is actually what is supposed to enhance the instrument, then as long as the contact is made and held securely in place well enough to transmit vibrations adequately through to register into a chromatic tuner, i would expect at least some sort of noticeable effect at least rivaling those reported on posted product reviews. im less than impressed.
when i was in the navy, we had this term called PFM (pure F'ing magic). whenever someone asked why things were the way they were, that was the answer given by senior sailors to their juniors if they didnt know how to answer. i never settled for that answer. and because of this. i must now purchase one of these little guys to prove to myself that either it does actually work, or my ears are just broken. haha