Sizing guide
ED ring size chart
Last updated: November 2026 · Published by FirmTech
Every FirmTech ED ring comes in one adjustable size that fits up to 5.5 inches (14 cm) erect girth.
FirmTech says one size fits 95% of men, because the hook-and-latch adjusts to your exact size. The MaxPR, Performance Ring and TechRing share the same girth range; what changes between them is how tight each one feels and how long you can wear it.
On this page
What size ED ring do I need?
If your erect girth at the base is 5.5 inches (14 cm) or less, any FirmTech ring fits you. There are no small, medium or large versions to pick from.
FirmTech rings open flat and fasten with an adjustable hook-and-latch, so the same ring sets to a looser or snugger tension. Above 5.5 inches, you are outside FirmTech's listed range.
FirmTech ED ring size chart
| Erect girth at base | MaxPR | Performance Ring | TechRing |
|---|---|---|---|
| Up to 5.5 in (14 cm) | Fits | Fits | Fits |
| Over 5.5 in (14 cm) | Outside listed range | Outside listed range | Outside listed range |
Why one size works
FirmTech rings use a peno-scrotal design: one loop around the base of the penis and one behind the testicles. The adjustable latch sets the tension, so the ring adapts to your size rather than forcing you into a fixed diameter.
How to measure for an ED ring
Measure when erect
Girth changes a lot between soft and erect, so measure at full erection.Wrap the base
Use a soft tape measure, or a piece of string, around the base of the penis where the ring will sit.Read the number
If you used string, mark where it meets and lay it flat against a ruler.Compare to 5.5 inches
At 5.5 inches (14 cm) or less, FirmTech rings fit.
Not sure? FirmTech purchases are covered by a 30-day money-back guarantee, and you can contact FirmTech before ordering.
Tightness is the real size choice
| Ring | Tightness | Safe wear time | Price |
|---|---|---|---|
| MaxPR | 5 of 5, Tightest | Up to 90 minutes | $60 |
| Performance Ring | 3 of 5, Comfort | Up to 12 hours | $60 |
| TechRing | 3 of 5, Secure | Up to 12 hours | $275 |
The MaxPR is slimmer and snugger than the Performance Ring on the same frame. For a step-by-step look at how it should feel, read the MaxPR ring fit guide.
Back to the main guide: ED rings for men, and how to choose the right FirmTech ring.
Common questions
Is there an ED ring size chart for FirmTech rings?
FirmTech rings come in one adjustable size, so the size chart is short: all three rings fit up to 5.5 inches (14 cm) erect girth. FirmTech says one size fits 95% of men. If your erect girth is above 5.5 inches, the rings are outside their listed fit range.
See this in the full FAQHow do I measure for an ED ring?
Measure when erect by wrapping a soft tape measure or a piece of string around the base of the penis. If the measurement is 5.5 inches (14 cm) or less, FirmTech rings fit. If you used string, mark it and lay it against a ruler to read the length.
See this in the full FAQWhat if my erect girth is over 5.5 inches?
FirmTech lists 5.5 inches (14 cm) erect girth as the fit limit for all three of its rings, so a larger girth falls outside that range. Contact FirmTech customer service through its contact page before ordering to ask about your fit. Purchases are also covered by FirmTech's 30-day money-back guarantee.
See this in the full FAQHow should the MaxPR ring fit?
The MaxPR should feel snug and firm at the base without pinching. It loops around the base of the penis and behind the testicles, and the hook-and-latch lets you set the tension. FirmTech calls it its snuggest hold, slimmer and tighter than the Performance Ring. If it hurts, loosen it or take it off.
See this in the full FAQDo I put on an ED ring before or after an erection?
FirmTech says its rings are designed to go on when you are soft, so you can put one on discreetly ahead of time. The open hook-and-latch design means you do not have to stretch a closed loop over an erection. Fasten it snug but not tight, then adjust as needed.
See this in the full FAQWhat does a peno-scrotal fit mean?
A peno-scrotal fit means the ring has two loops: one around the base of the penis and one behind the testicles. FirmTech says this anatomical design spreads pressure evenly instead of concentrating it in one thin band. All three FirmTech rings, including the MaxPR, use this same peno-scrotal design.
See this in the full FAQ