From 665 Leather:
The Wedge by Sport Fucker! This is hands-down the BEST basic, stretchable cockring on the market! Made with high quality TPE, this ring can be stretched to fit almost any size cock.
Being extremely reductive in design, The Wedge offers the slimmest profile possible to get the job done. I.E. job being: pushing your package up and holding juices in while not cutting into the skin or choking out your cock.