The 40mm size is a perfect fit for me. The ring is comfortable and not too tight so can be worn for extended periods when not ‘at attention’….but when the sap rises the ring hugs snugly to create that fantastic bulging feeling. Superb.

The tear drop shape allows for the underside to sit without excessive restriction.

If you normally wear a 40mm or 45mm round ring then the 40mm Primal should be a pleasant experience.

I also think 2 or 3 rings worn together would be even better, but Primal are now sold out of the 40mm so I will have to wait for that experience.

Great product at a reasonable price.

So….come on .Primal, get yourself restocked with the 40mm rings !

great product but users should order 1 size smaller than measured. The ease of application and design are so good that you will probably need 5 mm less to ensure a snug fit.

Well crafted and designed. This ring could easily be worn all day.

These are the absolute best rings. The fit is amazing and there is no other brand or style that can match it. I have been wearing rings for years and these are by far the best. 45mm is the standard. I would go down one size for the silicone. Anyways would love to see some more products. Maybe different colors.

I started out with the 45mm Power Flex. I usually wear this size in other rings. I ended up getting the 40mm. I thought it was just right, but a little too thick. About a week later, I ordered the Fusion and then got the Energy in their promo of $10 off- both in 40mm. They are just right. I do like the size and finish of the Fusion over the other one. I'm used to spending several hundred dollars on high end sterling silver and gold rings. These are perfect for what I need. I agree with others on the sizing. Because of the shape, you need to go down on your normal size. I could wear the 45mm, but it would have more of a chance of slipping off. With the 40mm, I can still get one finger under it and it is more secure. I think I'll try the 40 mm Pulse next so I don't set off metal detectors when I travel! : - )