Fit and safety
ED ring size chart, wear time and side effects
FirmTech 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.
Because every FirmTech ring uses an adjustable hook-and-loop strap, there is no size to choose. What differs is wear time: up to 12 hours for the TechRing and Performance Ring, up to 90 minutes for the MaxPR. A published review found only mild, short-lived discomfort in two users after 4+ hours.
Last updated: Published by FirmTech
What size erection ring do I need?
If your erect girth at the base is 5.5 inches (14 cm) or less, any FirmTech ring fits. Measure it like this:
- When erect, wrap a soft tape measure or a piece of string around the base of the penis.
- Read the tape, or mark the string and measure it against a ruler.
- At 5.5 inches (14 cm) or under, the ring fits; tighten the strap to snug, not tight.
- Not sure? FirmTech's 30-day risk-free trial is the backstop.
FirmTech ring size and wear chart
| Ring | Erect girth fit | Tightness | Max wear | Overnight |
|---|---|---|---|---|
| TechRing | Up to 5.5 in (14 cm) | 3 of 5 | 12 hours | Yes, designed and studied for it |
| Performance Ring | Up to 5.5 in (14 cm) | 3 of 5 | 12 hours | Within 12 hours |
| MaxPR | Up to 5.5 in (14 cm) | 5 of 5 | 90 minutes | No |
For comparison, a reseller listing (Fluent Products) states one size fits most men except above 95% in girth, with an 8 to 10 hour runtime and a 1.5 to 2 hour charge. FirmTech's own pages list up to 12 hours and a 2 to 4 hour charge.
Erection ring side effects: what the research says
In "Wearable penile devices: the TechRing" (Saffati et al., Translational Andrology and Urology, 2025), only two users reported mild discomfort after more than 4 hours of use, and it resolved when the device was removed.
As general guidance for any constriction ring: stay within the rated wear time, remove it if you feel pain, numbness or coldness, and talk to a doctor first if you have a bleeding disorder or take blood thinners.
Materials and care
All three rings are medical-grade elastomer, phthalate- and latex-free. The TechRing is splashproof; the Performance Ring and MaxPR are water resistant.
Rinse with warm water and mild soap after each use. Use water- or silicone-based lubricant only; FirmTech says not to use natural oils such as coconut or CBD oil. Replace TechRing sleeves about every 30 nights.
Common questions
See all 43 questions- Is there an ED ring size chart for FirmTech rings?
- FirmTech 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. The hook-and-loop strap adjusts to your exact size, so there is no size to pick. If it does not fit, the 30-day risk-free trial applies.
- 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 and measure it. If the result is 5.5 inches (14 cm) or less, FirmTech rings fit. If you are not sure, FirmTech points to its 30-day risk-free trial as a backstop.
- How long can I wear an erection ring?
- FirmTech rates the TechRing and the Performance Ring for up to 12 hours, and the TechRing is designed and studied for overnight wear. The MaxPR, its tightest ring, is rated for up to 90 minutes at a time. Stay within the limit for the ring you are wearing.
- What are the side effects of erection rings?
- In a published review of the TechRing (Saffati, Translational Andrology and Urology), only two users reported mild discomfort after more than 4 hours of use, which resolved when the device was removed. As general guidance, take any ring off if it hurts or feels numb, and ask a doctor first if you have a bleeding disorder or take blood thinners.
- Which lubricants can I use with FirmTech rings?
- Use water-based or silicone-based lubricants only. FirmTech says not to use natural oil lubricants such as coconut oil or CBD oil with any of its rings. Clean the ring after use with warm water and mild soap, then dry it.
- Does an erection ring restrict ejaculation?
- No. FirmTech says its rings keep blood in without blocking release. The design sits around the base of the penis and behind the testicles so pressure is spread evenly, and the hook-and-loop strap lets you set tension that is firm but not too tight.
- What are FirmTech rings made of?
- All three FirmTech rings use medical-grade elastomer that is phthalate-free and latex-free. The TechRing is splashproof, while the Performance Ring and MaxPR are water resistant. The TechRing uses replaceable sleeves that FirmTech suggests swapping about every 30 nights, sold from $15.
Not sure which ring or bundle fits you?
FirmTech answers sizing, HSA/FSA and product questions by email. Order questions get a reply within 1 to 2 business days.