Enso rings are silicon wedding bands. They were created to provide a safer alternative to metal bands, which can be easily damaged or lead to ring avulsion. The initial consumer market was athletes or people who work with their hands (surgeons, landscapers, mechanics, welders, etc.), but the rings have become popular among individuals who simply like the look or prefer a less expensive alternative to traditional bands.
The bands run at around $11-$40, and come in a variety of different sizes, colors, and patterns. Some look like metals, while others are bright and can be stackable. I have one and wear it all the time, especially while climbing and at the gym- it is super comfortable and my original ring is increasingly just being used on fancier occasions.
The rings are well-designed, and provide a personalized touch with many alternatives to something that a lot of people wear every day. They are marketed as beautiful, fun, and practical, and numerous companies have cropped up recently, selling a similar product. They rings also appeal to many individuals in younger generations, who increasingly shy away from expensive consumer products and value experiences and the uniqueness of such a product.