The Double Helix from Cal Exotics is a unique two-ring, detachable cock ring set. One ring goes around the shaft of the penis, while the other goes around both the penis and scrotum. The rings are detachable and they can be custom cut to fit according to your size. Using the two rings together can help maintain an erection by restricting blood flow from the penis. It can be worn during sex with a partner or during masturbation. It's important not to wear them longer than 20 minutes.

The material is rubber and has an EdenFantasys safety rating of only three to due its porous quality. The material is very soft. However, when it is worn it tends to grab and pull pubic hair, so a little personal grooming may be necessary to minimize discomfort. The material can be safely used with both silicone and water-base lubricants. The rings will stretch to fit and the tightness of the rings' fit depends on how much length is trimmed and your size. There is very slight rubber odor to the material, but it's hardly noticeable.

The Double Helix consists of two rubber rings, which are actually soft hollow rubber tubes. These two tubes are joined together by a thin band, but this can be removed and the rings can be used individually. Each tube has a tiny plastic nub on one end which fits into the other, hollow end of the tube, forming a ring. The connector has to be pushed into the other end and it will stay in place fairly well. To disconnect, simply pull it apart.

It can be custom cut to fit your particular dimensions. To do this, measure the circumference of your erect penis with a measuring tape, as well as the circumference around both the scrotum and penis. Then, measure this distance against the rubber lengths and cut to match. Because you can't undo the cut, you may want to leave it a little longer at first and try it on for size. It can always be trimmed smaller later.

As a cock ring, it functions fairly well. It will constrict the blood flow as any other cock ring would do.

The connectors can be a little difficult to snap into place, so I'd recommend putting the rings together and putting them on prior to getting an erection. Although it is possible to put them on an erect penis too, just more difficult. Having the connectors is a nice feature because the rings can be pulled apart and taken off quickly when you are done using them. If the ring is trimmed down to a very tight fit it might pull apart under the strain.

It can be washed with warm water and soap, then left out to air dry. Before storing, make sure the inside of the tubing is dry.

This product comes packed in a plastic box which is much larger than the product itself and wouldn't be useful for storage. However, the rings are very compact and storage space really isn't a factor.

This is a very nice product for its price, so for me it rates a solid four. If it's trimmed right, it works very well, and I like the look of double helix rings when they are on. I may plan on cutting the rubber rings down a little more for a tighter fit. I know that if I trim it too much, I'll have to throw it away, but I'll have a good estimation of what length I'll need when I buy a more permanent, silicone, cock ring in the future.