Ball bags intended for bondage play are typically made of leather, PVC or rubber. The opening of the bag typically has a strap drawn tight around the base of the testicles and may feature means for locking. Most ball bags are large enough only to accommodate a flaccid penis and are designed to make erections uncomfortable. Some models incorporate weights for stretching the genitals. Some male sadhus (or ascetics) of the Vaishnava branch of Hinduism wear as a symbol of austerity an arbandh, or a metal ball bag slung on a girdle about the waist.