Choose a base ring by comparing clearly defined measurements and ring shape—not by selecting the tightest available option. A number such as 45 mm may describe an inner diameter, while your tape measurement is a circumference. Those are not directly comparable, and a numerical conversion alone cannot establish fit.
What the base measurement refers to
The intended ring position is around the base of the penis and behind the scrotum, not around the shaft alone. A gentle circumference reading at that position can be recorded as a reference. Do not pull a tape tight, tie a loop or compress tissue to make a smaller measurement. Repeat the same method at another time and retain each result.
For the step-by-step record, use the measuring guide. This page focuses on interpreting those notes when looking at a ring selection.
Inner diameter and circumference are different
| Value | Meaning | Example, not a fit recommendation |
|---|---|---|
| Inner diameter | A straight distance across a circular ring’s inner opening. | 45 mm = approximately 1.77 inches. |
| Inner circumference | Distance around a circular inner boundary. | A 45 mm circle has a circumference of approximately 141.4 mm. |
| Body circumference | A soft-tape reading at a stated position. | A similar numerical circumference does not prove that a rigid ring is suitable. |
The formulas for a circle are C = πD and D = C ÷ π. Convert inches to millimeters by multiplying by 25.4. Keep the original measurement and round only the displayed result. The diameter and circumference guide explains why this calculation does not fully describe oval or curved rings.
Check shape and configuration as well as the number
Record whether the ring is round, oval or curved, and how it connects to the cage. A nominal size cannot capture its entire profile. Do not assume that a 45 mm ring from a different model is interchangeable or will make the same contact with the body.
Resin Inverted Chastity Cage – Black / Pink
This resin model offers a standard three-ring set with 41, 46 and 51 mm rings, or a four-ring configuration that adds 57 mm. The set option is explicit. It gives you documented choices within that model, not evidence that any particular ring will fit or that a larger set is always preferable.
Keep a short comparison record
| Your note | Product note |
|---|---|
| Separate repeated circumference readings | Ring measurement and unit |
| Any uncertainty about position or method | Shape and attachment |
| Symptoms from an existing fit, if any | One selected ring or included set |
| Questions still unanswered | Exact product link and option labels |
If the readings sit between available options, use the between-sizes checklist instead of automatically rounding up or down. The Size Guide helps organize the comparison; it is not a substitute for an individual fit assessment.
Stop signals override the size chart
Shifting or rotation can indicate a fit or assembly problem, but pain does not prove that you simply need to “get used to” a ring. Shape, surface condition and the cage connection also deserve attention. Do not tighten a strap or choose a smaller ring to suppress an unresolved problem.
Stop using the device if there is pain, numbness, swelling, discoloration, broken skin, or difficulty urinating. Remove it if you can do so safely; seek urgent medical help if it is stuck or symptoms are severe. Do not force removal or wait for painful pressure to become tolerable.