Add to your toybox with adjustable placement steel beads to distribute contact points for a variety of sensations. Sold as a pair.  (Each is unipolar making this a bipolar set)

2mm outside diameter, 1.75mm inside diameter for VERY SNUG connections to pins. Get an extra leadwire so you don't have to disconnect these once set up. The thin rubber may snap if stretched too much. 

Note: Cord locks size may vary due to manufacturer.