ED ring size chart: one size, adjustable fit

FirmTech rings come in one adjustable size that fits about 95% of men, up to 5.5 inches (14 cm) of erect girth. The hook-and-loop strap sets the tension to your exact size, so there are no small, medium or large options to pick. Measure your erect girth at the base, and if it is 5.5 inches or less, any FirmTech ring fits.

Last updated: November 2026 · Published by FirmTech

What size ED ring do I need?

You need no size choice with FirmTech: one size fits up to 5.5 inches (14 cm) of erect girth, and the strap adjusts. If you measure above that, FirmTech rings are not designed for you. If you are unsure, the 30-day money-back guarantee covers a wrong fit.

FirmTech ring size chart

ED ring size chart for FirmTech rings, by erect girth at the base, as of November 2026
Erect girth (inches)	Erect girth (cm)	Fits TechRing, Performance Ring and MaxPR?
4.0 in	10.2 cm	Yes, all three rings
4.5 in	11.4 cm	Yes, all three rings
5.0 in	12.7 cm	Yes, all three rings
5.5 in	14.0 cm	Yes, the upper limit
6.0 in	15.2 cm	No, above the 5.5 in limit

Centimeter values are converted from inches. The only fit limit FirmTech states is 5.5 inches (14 cm) of erect girth. The VaxAid Deluxe pump, sold in a TechRing bundle, has a separate range: 5 to 7 inches of erect length.

Tightness by ring

How snug each FirmTech ring feels, by FirmTech's own ratings
Ring	Tightness	Wear time	Choose it if
TechRing	3 of 5, secure	Up to 12 hours	You want a secure fit plus tracking
Performance Ring	3 of 5, comfort	Up to 12 hours	You want comfort first
MaxPR	5 of 5, tightest	Up to 90 minutes	You want the snuggest hold

Fit facts

Why FirmTech uses one size

Instead of fixed diameters, FirmTech rings use a patented hook-and-loop strap. You set the tension yourself each time, from comfortable to snug, so one ring covers erect girths up to 5.5 inches (14 cm).

The ring loops around the base of the penis and behind the testicles. That peno-scrotal shape, designed with urologists, spreads pressure across a wider area. The rings are soft, medical-grade elastomer with nothing hard or rigid, and they go on while you are soft.

Sizing by the numbers

Of men fit, per FirmTech: 95%
Maximum erect girth: 5.5 in
Same limit, metric: 14 cm
Size for all three rings: 1
To return if it does not fit: 30 days
VaxAid Deluxe pump, erect length: 5 to 7 in

How to measure for an erection ring

Step 1
Get a soft tape
Use a soft tape measure, or a piece of string and a ruler.
Step 2
Measure erect
When erect, wrap it once around the very base of the penis.
Step 3
Read it
Note the length where the tape meets. Use inches or centimeters.
Step 4
Compare
5.5 inches (14 cm) or less: FirmTech rings fit. Above that: they are not designed for you.

Fits? Pick your ring on the ring comparison or browse FirmTech erection ring accessories and bundles.

Common questions

Is there an ED ring size chart for FirmTech rings?: FirmTech rings come in one size that fits about 95% of men, up to 5.5 inches (14 cm) of erect girth. The hook-and-loop strap adjusts to your exact size, so there are no small, medium and large options to choose between. Measure your erect girth at the base to check.
How do I measure for an erection ring?: When erect, wrap a soft tape measure or a piece of string around the base of the penis, then measure the string against a ruler. If it measures 5.5 inches (14 cm) or less, FirmTech rings fit. If you are not sure, FirmTech's 30-day money-back guarantee covers you if the fit is wrong.
What if the ring doesn't fit?: Return it. FirmTech offers a 30-day money-back guarantee, and you can start a return online through its returns portal with your order number and email. If your erect girth is above 5.5 inches (14 cm), FirmTech rings are not designed for you, so measure before ordering.
How do I put on a FirmTech ring?: It takes seconds. Unhook the latch and open the loops, place one loop under the testicles and the other around the base of the penis, then adjust the tension until it is snug but not tight. FirmTech rings are designed to go on when you are soft, so you can put one on ahead of time.
Does the VaxAid Deluxe pump fit everyone?: No. FirmTech lists the VaxAid Deluxe water-based pump as fitting 5 to 7 inches erect. It is sold in a bundle with the TechRing for $499 instead of $574, a $75 saving. Check your erect length before choosing that bundle, and consider a different bundle if you fall outside that range.
What's the difference between the Performance Ring and the MaxPR?: Both cost $60, use the same doctor-designed peno-scrotal shape and fit up to 5.5 inches of erect girth. The MaxPR is slimmer and snugger: FirmTech rates its tightness 5 of 5 against 3 of 5 for the Performance Ring, and limits MaxPR wear to 90 minutes against 12 hours.

Read all FirmTech ring, RingMate and bundle questions

Measured and ready?

Every FirmTech ring fits up to 5.5 inches of erect girth, with 30 days to return it.

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