For those who prefer a more lifelike feel, this silicone version is designed with an extra size for a smoother progression, increased strength, and enhanced sensation while training the three sphincter muscles and surrounding skin. This 4-piece silicone system is designed to relax and strengthen the sphincter muscles, enhance skin elasticity, and support comfort, control, and gradual progression at every stage. Lubricant: Recommend using water-based, hybrid-silicone, or another toy-safe lubricant only. Materials:Made from 100% hyper-realistic, food grade, platinum-cured silicone.Dimensions:Level 1: Total length: 4.8” (12.2 cm) Insertable length: 4.3” (10.8 cm) Diameter: 0.9” (2.2 cm) Circumference: 2.8” (7.1 cm) Level 2: Total length: 5.5” (14 cm) Insertable length: 4.9” (12.5 cm) Diameter: 1.1” (2.8 cm) Circumference: 3.5” (8.9 cm) Level 3: Total length: 5.8” (14.8 cm) Insertable length: 5.2” (13.1 cm) Diameter: 1.3” (3.2 cm) Circumference: 4.1” (10.4 cm) Level 4: Total length: 6.1” (15.6 cm) Insertable length: 5.4” (13.8 cm) Diameter: 1.4” (3.6 cm) Circumference: 4.4” (11.2 cm)