Introducing the STACKER by OXBALLS studios that was designed for nuts. The name says it all because this ring was meant for stacking, so pick up more than one to increase the stacking fun. The STACKER is about an inch tall, and tight enough to grip your sack. Start with one and add another to feel the stretch. The STACKER is made of TPR (Thermoplastic Rubber) that has the stretch ability to increase to more than double its size. The fun doesn't end with your nuts the STACKER makes a tight thick cockring as well. Do Not Use Oil Based Lubes with this product.