Features a dual-density, multi-configuration design for massage and knot release. Roll against your body weight for deep massage or use in-hand for targeting specific trigger points. FEATURES: - Dual-density (think golf and lacrosse ball) for massage and trigger point release - Roll against your body weight or use in-hand to relieve soreness and target trigger points - Convertible dual yellow “knob” works like a massage therapist’s knuckles or elbows - Durable, non-slip surface for use in any environment