The Nexus O-Max is made of 100% silicone, but as for flexibility its definitely towards the stiffer end of the density range. The silicone of the O-Max has a velvet/matte finish that is good for holding lubes - a definite plus for an anal toy.
The Nexus O-Max is a silicone oval, 4-3/4" high by 4-1/8" wide, with a break at one end creating the prostate arm and the external perineum/control arm, which the designer calls the lovehandle. The O-Max is beefier all around than the Nexus O, with a 1-1/4" diameter curved shaft connected to 1-5/8" diameter balls. The beefier shaft and balls not only makes the O-Max more filling, but also produce a firmer toy for stronger stimulation. The larger size of the O-Max also reaches a little further inside than the Nexus O, able to stimulate the top of my prostate during use.
While the interior ball is stimulating your prostate and surrounding organs, the ball on the lovehandle is stimulating the perineum area and serving as a handle if you need to reorient the O-Max or desire stronger stimulation. This leaves the middle ball, the positioning of which I found a little confusing. The instructions recommend inserting the middle ball just inside the anus, where it can stimulate the anus from within. My body build didn't like that - full insertion led to very uncomfortable pressure on my internal organs. The designer of the Nexus O, Seb Cox, has an alternate set of instructions on his website Seb's instructions that recommend placing the middle ball just outside of the anus to stimulate the anal area from the outside, which I found much more comfortable.
The size of this toy combined with the abrupt taper of the balls makes it better suited for more advanced users.
This is one of the more discreet prostate massagers on the market. It doesn't scream "sex toy", it barely even whispers it. If someone were to ask what it was you could tell them a number of alternate uses, such as "it's a clip to keep your pants up when you're in the mud" or "it's a funnybone protector". Unless someone already knew what it was you'd be pretty safe taking it through the airport.
The Nexus O-Max (and the similar but smaller Nexus O) are a very different take on the prostate massager. The semicircular design and springy material make for a highly stimulating toy that moves noticeably differently from all the other prostate massagers that I've tried. The bad news is that the Nexus O requires much more work to figure out how to use, since optimal use is dependent on the user's internal anatomy.
My guess is that there are some people who love the Nexus O-Max the first time they use it, some who never can get it to be comfortable, and the vast majority who (like myself) need to put a lot of work into figuring out how the O-Max works with their personal layout.
After my struggles trying to get the O-Max working (see the experience section), my wife wasn't interested in trying it out anally. Used vaginally (one arm inserted, one arm resting against/above the vulva), the Nexus O produced interesting sensations but was not stellar, as the toy was a bit hard to maneuver while maintaining contact at both points. It would be better used with one end hand-held as a G-spot massager with clitoral stimulation provided by a hand or other toy.
Since it is made of silicone, the O-max is very easy to care for. It's compatible with all water and oil-based lubes, giving you many options. While Nexus does not recommend the use of silicone lubes on the O-Max, my tests with a silicone lube (Futuring GetMaxxx) left no permanent damage (there was some temporary discoloration, but that went away after an hour).
Clean-up after use was simple as well - the O-Max can be cleaned with soap and water or any other toy cleaner, and sterilized (if you want) with either 10% bleach solution or by boiling. Sterilization between users is probably the best approach, as the pronounced curve of the O-Max makes it difficult to use a condom successfully.
The O-Max came in a clear plastic box that displayed the product attractively without using too many materials. While the packaging could be used to store the O-Max, it's not strong enough to stand up over the long-term.
The design of the Nexus O-Max is difficult to get around, both physically and mentally. Unfortunately, the instructions don't always help. While they are more detailed than the instructions included with most sex toys, the O-Max is specialized enough that they weren't enough. Here are some of the things that I discovered about the O-Max, in no particular order:
Before you try the O-Max do two things: wash it, and grab both end balls and flex it about 20 times to get it a little loosened up.
Two hands are necessary for insertion. You need to flex the external arm out in order to insert the prostate arm in the most comfortable manner. I tried inserting the toy "backwards" (with the external arm pointing out and up towards your back), and while insertion was easier turning the toy around was very uncomfortable.
I had the best luck inserting the O-Max while squatting.
The instructions recommend inserting the middle ball just inside the anus. This doesn't work for my body type. When I do this the O-Max is very uncomfortable. It can also be used with the middle ball just outside the anus, which was much more comfortable for me. The first few times I tried the O-Max with the middle ball outside the anus I had difficulty keeping it in. I then found that if you hold the O-Max completely inserted for a few minutes (5-10) the prostate ball "hooks" around something inside (probably the prostate) and holds the toy in. You don't need to use your hands - a chair or bed can be used to hold the toy in while you're getting used to it.
My journey with the O-Max is a story of frustration, hope, and a little pain. My first try was awful - I didn't know how to use the toy, and the instructions weren't clear enough to tell me how (note to manufacturers: line drawings are a great addition to instructions!) I pulled it out of the box, washed it, lubed it up, and tried to stuff it in to the second ball. Result: OWWCH! The curve was just too much. The second try was similar, although I flexed the O-Max first to loosen it up a bit. I was able to insert it backwards and turn it around, but things were still uncomfortable.
I wasn't sure I wanted to try again, but I had made a deal. Fortunately, Jimbo Jones (who reviewed the Nexus O) steered me towards Seb's alternate instructions, which were much more comfortable - except the O-Max kept sliding out.
Eventually I sat down on a chair to hold it in, and when I stood up I had a pleasant surprise: the O-Max had slipped around something inside me and was now staying in like it should. Things got much better from there, although I still have times when something slips where it shouldn't be and things get a bit uncomfortable for a while. When I do something right, the O-Max slides around and feels really good. And it's getting better every time. While I have yet to be able to get a prostate orgasm from the O-Max, it's starting to look like it can happen now, whereas those first few times I wasn't sure if I was using a sex toy or a torture device.
The moral of this story: don't get this toy unless you're experienced, but if you do get it be willing to experiment with it and come back.
There's a third moral, too: If something hurts, stop and try it differently. I should know this, but sometimes I do get all 'macho". When I got macho with the O-Max, the pain shut things down for about an hour and a half.