Oxballs Neo Short Ballstretcher is made of a new pressure cast silicone hybrid with firm grip and stretch. This grippy stretch really keeps those nuts down in their sack and will not lose its shape or size over time. Safe with all lubes. This toy will not pinch or cause a burning feel some get using neoprene on their sack. Made from 95 percent silicone, 5 percent neoprene. The Neo Short will fit any sack and can be stacked as you grow.