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ED ring size chart

ED ring size chart and fit checker.

FirmTech's ED rings come in one adjustable size that fits up to 5.5 inches (14 cm) of erect girth, which FirmTech says covers 95% of men.

Last updated: November 3, 2026

What size ED ring do I need?

With FirmTech, you do not pick a size. Every FirmTech ring, the TechRing, Performance Ring and MaxPR, has an adjustable hook-and-loop strap that fits up to 5.5 inches (14 cm) of erect girth. Measure around the base when erect; at 5.5 inches or less, any of the three fits.

Above 5.5 inches, contact FirmTech before buying. Fixed-size rings from other makers do need a size choice, so check each maker's own chart.

ED ring size chart

FirmTech ring fit by erect girth at the base
Erect girthCentimetersTechRingPerformance RingMaxPR
4.0 in10.2 cmFitsFitsFits
4.5 in11.4 cmFitsFitsFits
5.0 in12.7 cmFitsFitsFits
5.5 in14.0 cmFitsFitsFits
6.0 in15.2 cmAbove stated rangeAbove stated rangeAbove stated range
6.5 in16.5 cmAbove stated rangeAbove stated rangeAbove stated range

Fit range as stated by FirmTech: up to 5.5 inches (14 cm) of erect girth for all three rings. The VaxAid Deluxe pump sold in a FirmTech bundle is listed separately as fitting 5 to 7 inches erect.

Check your fit

Enter one measurement in inches or centimeters. Nothing is stored or sent anywhere.

Assumptions: FirmTech's stated maximum of 5.5 inches (14 cm) erect girth, and 1 inch = 2.54 cm. This is an estimate based on one measurement, not a medical or fitting decision. Orders are covered by a 30-day money-back guarantee.

Sizing, explained

What does ED ring size mean?

ED ring size is the circumference a ring is made to fit, measured as girth at the base of the erect penis. Fixed rings come in set inner diameters, so a ring that is too small can pinch and one that is too large does little. That is why size charts exist.

FirmTech solves it differently. Its rings use a patented hook-and-loop strap and a peno-scrotal shape that sits around the base and behind the testicles, so one ring adjusts to your exact size. FirmTech says one size fits 95% of men, up to 5.5 inches (14 cm) erect girth, and the pressure stays firm but never too tight when set correctly.

Fit numbers

Maximum erect girth, all FirmTech rings
5.5 in
Same maximum in centimeters
14 cm
Share of men FirmTech says one size fits
95%
Money-back guarantee if the fit is wrong
30 days

How do I measure for an erection ring?

  1. Step 1: Wait for a full erection

    Girth changes with firmness, so measure when fully erect.

  2. Step 2: Wrap a soft tape or string

    Go around the base of the penis, snug against the skin but not tight.

  3. Step 3: Read the length

    If you used string, mark it and measure it flat against a ruler.

  4. Step 4: Compare to 5.5 inches

    At 5.5 inches (14 cm) or less, FirmTech rings fit. Use the checker above to confirm.

Back to the FirmTech erection rings overview

Common questions

Short answers here. All 49 questions are on the FirmTech erection ring FAQ.

Will a FirmTech ring fit me?
Most likely. FirmTech says one size fits 95% of men, up to 5.5 inches (14 cm) of erect girth, and the hook-and-loop strap adjusts to your exact size. All three rings share that same fit range, so there is no size to pick at checkout. More in the FAQ
How do I measure for an ED ring?
When erect, wrap a soft tape measure or a piece of string around the base of the penis and measure the length. If it is 5.5 inches (14 cm) or less, FirmTech rings fit. Our ED ring size chart and fit checker give you a quick read. More in the FAQ
What if my girth is over 5.5 inches?
FirmTech states a fit range of up to 5.5 inches (14 cm) of erect girth. If you measure above that, contact FirmTech before ordering so the team can advise you. Orders are also covered by FirmTech's 30-day money-back guarantee. More in the FAQ
How tight should an erection ring be?
Snug, never painful. The ring should hold firm pressure at the base without pinching, numbness or color change. The adjustable strap on every FirmTech ring lets you set the tension, so loosen it or remove the ring if anything feels wrong. More in the FAQ
How do I put on a FirmTech ring?
Hold the loop open and drop the testicles through it, then set the second loop around the base of the penis, so one loop sits behind the testicles and one at the base. Adjust the strap until it is snug but not tight. It takes a few seconds. More in the FAQ
What if the ring does not work for me?
Try adjusting the tension first, since a slightly snugger setting often makes the difference. If it still is not right, FirmTech's 30-day money-back guarantee covers you. Contact customer service with your order number for a return or help. More in the FAQ

It fits? Pick your ring.

All three FirmTech rings share the same adjustable fit, so choose by goal, not size.

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