I have found two different functions for this product. The first function is the intended function, as an accessory to use two Vac-U-Lock attachments at the same time. The second use is without any other items. Because this is still a plug, this toy can also be used as a butt plug.

According to the Vac-U-Lock system, this is a "3," meaning it's an accessory that works with all complete sets and attachments within the Vac-U-Lock system. Note: it does not say anything about compatibility with any accessories.

What this product does is connect two compatible (all, according to box and included insert) attachments to create your own combination to your desire. To use, you first put the plug into the harness and snap it in. Then you use "Vac-U-Powder" on the attachment and insert the plug.

A list of a small selection of items is printed on one side of the insert, but there are "over 50 items" available. Complete sets include products such as the "E-Z Rider Ball" and "Leather Ultra Harness," and attachments include products such as "6 inch UR3 Cock" and "8 inch Realistic Cock."

This product also works as a butt plug. With using lube (but NOT petroleum-based), this toy works as a butt plug would. It can be used to help train for larger objects, or it can be used on its own if a small size is preferred.

According to EdenFantasys, this product is made of rubber. However, I honestly feel that it is made of plastic (and the snaps are made of a type of metal).

The product feels very hard and is in no way soft, which is why I believe it is made of plastic. The product has no taste or smell. It isn't too thick, which may or may not be a good thing if you're using it as a butt plug.

The design is simple; the harness attaches to it in the middle and there is a plug for an attachment on either side of the product. I think it is made well, due to the product being very sturdy and firm. The snaps are easy enough to snap in and unsnap. This product is compatible with all Vac-U-Lock sets and attachments (according to the insert and box). The look isn't too attractive, but it won't really be seen because it will be inside an attachment and/or the butt. And if used as a butt plug, it is good for beginners (or those who have beginners as partners because it is a double plug) due to the small length and small diameter.

According to the included insert, the harnesses are adjustable up to a waist size of 53". But going on this product alone, this product works with all Vac-U-Lock harnesses (according to both the box and insert).

As a butt plug, it fits in well, especially if you're a beginner. It doesn't go too deep for your first go, and the wall between the two plugs works well if you're with a partner.

The product itself attached easily to the harness and the attachments. The snaps worked well, and it was easy enough to use the attachments. This product does its job very well; it attaches to the harness and allows two attachments at once.

As a butt plug, it performed well. I'm not a complete beginner to anal play, and it left me wanting for more. It was nice, and it would have been even better if this was my first time going into anal play.

According to the insert, the only lube that shouldn't be used are lubes with a petroleum base.

Cleaning this product is extremely easy. As being made of plastic (or rubber, which I still don't believe), it can be cleaned with soap and warm water. There are no parts to take off and clean, so the plug itself is extremely easy to clean.

According to the insert, you're supposed to clean the harnesses with some dishwashing liquid and water, then wipe it dry. This product however, doesn't need dishwashing liquid, only regular soap.

On the front of the box there is a picture of the product with writing saying it is compatible with all Vac-U-Lock harnesses and attachments. On one side, it says the same thing, but in a total of six languages. On the other side, it explains the Vac-U-Lock system (what "1," "2," and "3" mean in the system). On the back of the box, it just talks about how Vac-U-Lock has accessories for everyone and how the accessories are, once again, compatible with all harnesses and attachments.

The box only had two things inside. The plug was inside a bag (which is great for storage) and there was a Vac-U-Lock insert that has some complete sets, attachments, and accessories listed on one side and cleaning/compatibility/instructions on the other.

I really do believe that this product is made of plastic, not rubber as is listed on EdenFantasys. Besides that, I really enjoyed this product. Because I am not new to anal play, this product only made me beg for more. The product also worked will with the harness and attachments. The product works extremely well for both functions, as I listed.

I immediately tried using it as a butt plug as soon as I lubed it up. I loved it, but it kept me wanting more because I was no beginner to anal play.

With the harness, there were no complaints. It worked well. The snaps worked, it fit well in the attachments, and it was an overall great experience.