There are two aspects to vibration dampening.
1) Mass. More mass = better dampening overall. However, this is something that is a side effect of the amount of mass that the B-Stinger adds, and is not necessarily it's forte. B-Stinger helps stabilize the bow more than removes vibration.
More mass comes into play either by adding weight to the bow, more weight to the arrow, or both.
2) Dampening specific areas. Helping remove the resonance created by shooting the bow is where you're gonna see the most positive effect. Resonance is found everywhere - limbs, string, etc. Adding stuff like cat whiskers, string termination systems, and s-coil like devices all help reduce the bow's resonance.
On the bow that I shoot the B-Stinger predominantly with, I end up using both dampening and mass. My Bow Madness XL uses a 9.5" long extension tube that contains powder to dampen the resonance created, and uses a B-Stinger attached to the dampening tube to help eliminate torque and provide stability.
On my 3D and hunting bow, for stabilizing the bow with longer shots, I use a small dampening unit on the end of the B-Stinger (a discontinued Doinker 3" Vari-Tune) to act as a dampener while the 12" Pro Hunter B-Stinger is used with a 17 ounce weight to prevent bow torque and stabilize the bow.
-Steve
