Domestic pig bristle: medium to firm bristle for dry massage and wet use. Domestic pig bristle: soft to medium hard for dry and wet use. For a gentle to stimulating massage. Sisal bristles, in short: hard, vegan bristles for intensive dry massage. Sisal bristle, long: medium-hard, vegan bristle for stimulating dry massage. Sisal/horsehair mixture: medium-hard bristles for a stimulating dry massage.