Tungsten glans ring
I have been wearing glans rings for a number of years. I have a number of stainless steel O rings, I have a 60 grams stainless steel glans ring (5 mm thick, and 15mm wide ), I have a number of tungsten finger rings they are around 24 grams. I usually wear two of the finger rings to increase the weight. My favorite ring is a 120 gram stainless steel shaft colar. It is bulky ( 8mm thick and 16mm wide ).
The perfect glans ring would be the 5mm thick by 15mm wide ring, but instead of being made of stainless steel it would be made of tungsten. Tungsten is twice the weight of stainless steel. This ring in tungsten would weigh what the shaft collar ring weighed but it would be less bulky, and look nicer with the girl friend, for social nude recreation, or in the locker room.
If find a 120 gram glans ring combats turtling, and maintains gains. The constant light stretching might even add a little size over time. As an added bonus, it just plain feels good to wear. I am pretty much wearing it from the time I get up till I go to bed everyday.
I have checked with factories in China. After the initial cost of having the first ring produced and delivered to my door, which would cost around $270, I could get them made for about $24 plus shipping in lots of 20. This would be a nice looking surprisingly heavy ring ( tungsten is 1.74 times heavier than lead!). It could be left plain, or for a little extra gold colored. Tungsten and pure gold are similar in weight. I think an inside dimension of 25.4mm ( 1 inch ) to 25.8mm would work for most people. So the math with shipping is about $800 to get 20 tungsten glans rings. That would bring the individual cost to about $40 without shipping, so lets say around $50 for a very nice glans ring shipped to your door in US postage.