BiPolar EClip

+: lightweight, adjustment screw.
-: pricey, functional design
It won't hold on the "delicate bits" I have tried it on so far. Both my subjects and myself found it a painful experience. Might work better with an adaptor clipped onto the contact surfaces suitable for the delicate bit you are attaching it to.
In spite of having a gold sheet coating on the outside, it rusts on the sides after only the second usage, even after thoroughly rinising of the electro gel residue and drying it with a piece of cloth.
Could be a hit after some design improvements.