As far as windows go, the Master Series' Ass Bung 3 Inch Anal Dilator probably (definitely) won't give you much insight into your partners soul, but it WILL give you a great view into their butt! Aside from a classic shape, a crystal clear design and a silky smooth surface, the Bung is completely hollow through the middle, all the better for deep-diving penetration and lots of stimulating stretch.
Shaped into a mid-sized bulb, tapered slightly at the tip and widening out toward the middle, the Ass Bung sits snugly in your/their butt, placing exciting pressure on the anal walls while holding the anus open. A nice big base finishes off a sleek neck - it prevents too-deep penetration while also providing a very visible target, so to speak. Pop out the plug in the base for access.
In body safe scent-free TPE (thermoplastic elastomer) the Ass Bung is extra durable, very easy to clean, and a breeze to maintain. Clean it well before and after use with lots of warm soapy water or a good toy care fluid/foam. This anal tool can be safely used with any favorite water based lube - and lots of it.