This first-ever, transforming massage roller adapts for targeted massage. You adapt it to fit your massage by rearranging the nine Adaptive Massage Rings. Offered in varied sets of three sizes, these interchangeable rings, provide ultra-diverse massage options, from superficial to deep tissue compression. Each ring has variable patterns of raised ridges that promote circulation and release trigger points. Simply slide the rings on and off the roller to create limitless massage configurations. DESIGN & DETAILS: Each Revolve Roller has 9 Adaptive Massage Rings All Rings are interchangeable for unlimited targeted massage options Ultra-Fin Core length: 13" - Core dia: 4.375" Screw-in Retainer Caps on both ends of core Massage Rings use stabilizing grooves to slide on and off the Revolve Roller Rotating the ring one-quarter turn will vary the raised ridge pattern Red Low profile: 5.875" Grey Mid profile: 6.25" Green High profile: 6.625"