The Spartacus Endurance clamps are NOT, I repeat NOT, for beginners, or anyone new to nipple sensation play. They have quite a strong bite. Also those with larger nipples may find that these won't fit properly. Each clamp opens to allow for about 1/2" of space, and that wasn't enough to comfortably fit on my nipples. I had to forcibly squeeze my nipples into the clamps, which was very uncomfortable. For rougher sex play activities, clamping them on my outer labia felt nice, but not for extended periods of time.

The Endurance clamps feel nice enough when you work them in your hands. They are mostly made of metal, though no information is given as to what kind of metal the chain and actual clamps are made of, so be wary if you have any known metal allergies. Playing with the actual clamps in my hands, I thought they would be comfortable to wear. They are not weighted and the metal chain isn't too heavy.

The Spartacus Endurance nipple clamps are absolutely NOT, I repeat NOT, for beginners. Those with larger nipples may find problems getting the small clamps to stay fully attached. The look of the clamps is classically kinky, but when it comes down to it, they are a cheaply made product. The clamps are "alligator" style connected by a 10" metal chain and simple enough to operate (just squeeze them open). I had trouble fitting the clamps around my nipples, even when they were fully erect. When you squeeze each clamp open, the space is roughly half an inch which made it difficult to keep on my nipples.
On each clamp, there is black plastic that covers the handles of the clamps. In each plastic cover, a metal rod comes out and loops to the metal chain. This arrangement makes the placement of the clamps awkward when worn on the nipples. The chain isn't too heavy, but the rods were just unsexy and kind of made each clamp move in weird positions.

What attracted me to these clamps was the simple look and design, and the chain. But after 15 minutes of use, the metal rod protruding from one of the clamps came out. I didn't yank on the chain at all, nor did my boyfriend. I was wearing the clamps and repositioned myself in bed for doggy style sex. Then the rod came out of the clamp. I took off the clamps and inspected the clamps and chain and gently pulled on the other rod that was still connecting the clamp to the chain, and it popped out. Now all I have is two tiny alligator clamps that I occasionally put to use on my pussy lips for extra stimulation (I swear, it feels wonderful).

The rubberized tips of the clamps protect your skin from the sharp metal "teeth" inside (thus called alligator clamps). The rubber tips fell off repeatedly but that didn't bother me as much as the stickiness of the rubber on my nipples. After having my nipples clamped, my boyfriend or I would squeeze the clamps to release my sore nipples, and I felt an incredibly uncomfortable sticking sensation. The rubber sticks to your nipples and actually pulls on the skin when removed. It was just downright painful.

I had high hopes for this toy and was very disappointed by the shoddy performance. The tips stick to my skin and pull it, the chain broke off and the rubber tips keep falling off. I like the idea of nipple play but will definitely look into something better for the future.

While these clamps didn't work for me and all but fell apart in my hands, those with smaller nipples searching for intense nipple stimulation may find these enjoyable, but be careful of rough play; they may not last long at all, given my experience.