Attachments and accessories are everywhere. The fine folks at Doc Johnson felt it was their turn, so they devised a modular unisex product, which enables the user(s) to experience a large variety of strap-on attachments. Some of the optional sizes sent for review include 5.5-inch, 6-inch, 7-inch, and 8-inch. They all work with their Ultra Harness and Vac-U-Lock System which features an adjustable waist band up to 44 inches. Each box includes a poster of the devices suitable for framing. They work great.