ED ring size chart

Will a FirmTech ring fit?

Last updated: November 2026

What size ED ring do I need?

You do not need to pick a size: every FirmTech ring comes in one adjustable size that fits up to 5.5 inches (14 cm) of erect girth, which FirmTech says covers 95% of men.

The hook-and-loop strap tightens or loosens to your exact size, so the same ring works whether you are toward the small or large end of that range. If you are unsure, FirmTech’s 30-day money-back guarantee covers you.

New to tracking? Start with our guide to nighttime erections tracking and choosing a ring.

Size chart

FirmTech ring size chart

FirmTech ED ring size chart by erect girth, from FirmTech’s fit guidance.
Erect girth	Metric	Fit
Up to 5.5 in	Up to 14 cm	Fits all three FirmTech rings. Adjust the strap to your size.
Over 5.5 in	Over 14 cm	Outside FirmTech’s stated fit range. FirmTech rings are not designed for this girth.

Measure

How do I measure erect girth?

Step 1
Wrap
When erect, wrap a soft tape measure or a piece of string around the base of the penis.
Step 2
Read
Read the tape, or mark the string and lay it flat against a ruler.
Step 3
Compare
If it reads 5.5 inches (14 cm) or less, every FirmTech ring fits.

Feel

Which FirmTech ring feels tightest?

Tightness

Same size range, different hold

Size and tightness are not the same thing. All three FirmTech rings share the 5.5 inch fit range, but FirmTech rates their tightness differently: the TechRing 3 of 5 (secure), the Performance Ring 3 of 5 (comfort), and the MaxPR 5 of 5 (tightest).

The MaxPR is slimmer and snugger for maximum firmness, which is why FirmTech limits it to 90 minutes. The TechRing and Performance Ring are rated for up to 12 hours.

Getting it right

Snug, never tight

The rings are designed to go on while soft. Open the latch, drop the testicles through one loop, bring the second loop around the base of the penis and fasten it snug but not tight. FirmTech says it takes seconds.

If it feels painful, numb or cold, loosen or remove it. Comfort is the goal: the adjustable strap exists so you set the pressure yourself rather than forcing your body to fit a fixed ring.

Common questions

See all 45 questions in the FAQ

What size ED ring do I need?: FirmTech rings come in one size that fits 95% of men, up to 5.5 inches (14 cm) erect girth. The hook-and-loop strap adjusts to your exact size, so there is no size chart to pick from. If your erect girth is over 5.5 inches, FirmTech’s rings are not designed to fit you.
How do I measure erect girth for a 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 the result is 5.5 inches (14 cm) or less, FirmTech’s rings fit. If you are unsure, the 30-day risk-free trial covers you.
Which FirmTech ring is the tightest?: The MaxPR is FirmTech’s tightest ring. It rates 5 of 5 for tightness on FirmTech’s scale, compared with 3 of 5 for both the Performance Ring and the TechRing. It is slimmer and snugger, and FirmTech limits its wear time to 90 minutes at a time.
How long can I wear an ED ring?: FirmTech lists up to 12 hours for the TechRing and the Performance Ring, and the TechRing is designed for overnight wear. The MaxPR, the tightest ring, is limited to 90 minutes at a time. Always follow the wear time for the specific ring you own.
What are FirmTech rings made of?: All three rings are medical-grade elastomer, phthalate-free and latex-free. The TechRing is splashproof, and the Performance Ring and MaxPR are water resistant. Rinse with warm water and mild soap after each use, and use only water-based or silicone-based lubricants.
How do I put an ED ring on?: Open the latch so the ring lies flat, drop the testicles through one loop, then bring the second loop around the base of the penis and fasten it snug but not tight. FirmTech says it takes seconds. The rings are designed to go on while soft, so you can put one on discreetly ahead of time.

Ready to pick your ring?

Every FirmTech ring is sold online at getfirmtech.com with free discreet shipping on orders over $100 and a 30-day money-back guarantee.

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