I have several. Steel wire, stainless donut, brushed aluminum and neoprene. I like them but theyre not so great to run in. Ive worn them to some nudist resorts but others ban jewelry. I usually wear one under my clothes at work just to enjoy knowing Im still free at heart.
I wear stainless steel cock and glans rings and have many of different sizes and weights and love them when walking the trails at local nude campground. I do get some comments. The added weight to the glans rings are a turn on and I can wear them while working under my clothes and feels and when I go commando, which I do all the time they show a nice rim. G
I just use the hardware store ones and am happy with them. A custom one would be better shaped but the stainless ones (I have a number or 28mm diameter rings) are just the Goldilocks size and I can stack them for different overall widths. One gives a little definition under clothes without the ring itself being obvious, while more add weight and hence swing among with a slight sensation of being captive. Mulitple rings may show ridges through clothing rather than just looking natural-but-prominent. The rings match my 40mm ones and I'd hate to be mismatched. Depending on the number and what I'm wearing, I can leave them on for many days.
I have worn them periodically for years. I acquired mine from gear essentials.com a set of three different widths. They are stainless steel and work much as you would expect. It swells the crown of my penis to 2x it's resting state. Feels amazing.