Erection Assistant Hollow Strap On 9.5 inches Black from Nasstoys of New York. Adjustable strap-on dildo for him, for her, for everyone! Comfortable harness. Hollow cavity. Phthalates freematerials PVC, Polyurethane PU and Polyester. Size waist 29 inches to 59 inches. Overall length 9.5 inches, insertable length 8 inches, outer diameter 2 inches. Nasstoys - Erection Assistant. Categories: Strap-Ons and Harnesses, PPAS or Prosthetic Penis Attachments, Body Harnesses.