This specific model is equipped with a urethral sounding dilator. Made from smooth, flexible medical-grade silicone, which clicks into the bottom of the device and goes into the opening of the urethra. The total length of the dilator is 20.5cm (8.07"), the insertable length is 20cm (7.87") and the diameter is 3.5mm (0.137")

Inner diameter 1.38" 
Insertable length 2.56" 
Waterproof Yes 
Splashproof Yes 
Specifications Inner Diameter 
 Cage: 3,5 
 Rings: 4,5, 5, 5,5, 6 cm 
Materials Polycarbonate