(Based on 2 reviews)
I've enjoyed leather, fabric & latex/rubber cock rings for years & avoided metal on the basis that if a metal ring was too constrictive all sorts of medical emergencies might ensue. Recently I've got into metal glans rings & thought I ought to experiment with a matching metal ring behind my balls (not interested in the base of the shaft). I measured the circumference behind my balls & wondered whether to go for a size bigger or (more exciting) exact measurement, or even less. This set removed any concerns; I quickly found that the exact measurement (55mm) was slightly loose for metal rings, so wanted to try successively smaller measurements. This is the perfect set for experimentation; I went from an initial 55mm (surprisingly loose, as initially measured) through 50, 45, down to 40mm for comfortable daily wear. The 40mm internal diameter is perfect for sex for me; tight when erect, it still let blood out of my erection & I could remove the ring with lube (best used when adding or removing a metal ring regardless). I'm happy to use a metal cock ring now & this set gave me the opportunity to experiment incrementally with smaller & smaller sizes. Always bear in mind the warnings about leaving a metal ring on when asleep (I wouldn't, unlike the right glans ring) & be acutely aware of dangerous symptoms of continuous wear when erect such as numbness or cold in your cock.
My partner and myself use these most in foreplay, primarily to get each other good and hard. They seem to assist us both in getting a firm and enduring erection which means that our orgasms tend to be more powerful. Would recommend using with a decent lubricant