On my second ring, based on measuring instructions I ordered a 50mm which would barely stay on. I’ve sized down to a 45mm and it’s pretty fairly loose but I can barely get my balls through it. Debating if I want to try a 40mm or call it a lose.

My 2nd ring purchased at 50mm.

Based on my experience with my 1st ring which was the Pulse Flex at 45mm.

More experience may lead me to order again but at 45mm.

I have a collection of different cock rings from Greek, Dutch and British designers but the Primal:Fusion is the most comfortable one so far. You can wear it 24/7 and you wont even feel it and it there when you need it. If it's not on, it's not in...

The shape of the primal rings is so much better than the round rings I have used in the past, highly recommended. I use the larger size for daily wear and one size smaller for romantic interludes.

Let me start by saying I have been an avid CR user for many years I’ve got a lot, I stumbled across Primal 1 evening and was impressed by the quality look and stylish finished these ring have. I instantly purchased the Power Flex Satin Black Ring 45mm. When I arrived I dint waste anytime putting it on! love that ring!
I recently purchased the Fusion Matt Stainless Ring. I’m pretty confident with my size for round rings being 47-48mm. I have a full set (4) curved SS CR from another designer and I bounce between the 45 & 47 ones depending on the use (45 for play 47 for daily).
Because there was an instruction link on measuring for Primal I decided to double check my measurements. My results varied between 45-50. I decided to go with the 45, when it arrived I was excited to get it on!
So I warmed it up, slapped on a little nut butter cream and away I went, that’s when things got tricky, the keyhole design is quite unique to Primal. I finally got it on and wow it was tight and I wasn’t even chubbed up, So before the blood rush, I took it off!
Looks like I will be getting a 50 down the road when an offer or sales comes up!