Buzzkill Bar Plugs?

Okay, I first inclination is to go straight to the gutter but these are supposedly actual cycling items. Since I’m still a novice in the ways of cycling, I’m looking for some advice/reviews if these little babies are worth the investment.

They’re advertised as having the ability to use ‘harmonic damper technology to cancel high frequency vibrations’, thus saving my hands from going completely numb on my 300 mile trek across Michigan.

I just really like the name............