Size chart
Published by FirmTech Last updated November 2026
You do not need to pick a size with FirmTech: one adjustable size fits up to 5.5 inches (14 cm) of erect girth, which FirmTech says covers 95% of men. The same limit applies to the TechRing, Performance Ring and MaxPR, and the hook-and-loop strap adjusts to your exact size.
New here? Start with the TechRing erectile tracker overview and ring chooser.
| Erect girth (inches) | Erect girth (cm) | FirmTech fit |
|---|---|---|
| Up to 4.5" | Up to 11.4 cm | Fits all three rings |
| 4.5" to 5.0" | 11.4 to 12.7 cm | Fits all three rings |
| 5.0" to 5.5" | 12.7 to 14 cm | Fits all three rings |
| Over 5.5" | Over 14 cm | Above FirmTech’s stated limit |
How to measure
Not sure? FirmTech offers a 30-day money-back guarantee. Tightness differs by ring even at the same size: the TechRing and Performance Ring are rated 3 of 5, while the MaxPR is rated 5 of 5, the tightest.
Estimate only, not a medical assessment. Assumes FirmTech's published limit of 5.5 inches (14 cm) erect girth for the TechRing, Performance Ring and MaxPR, and 2.54 cm per inch. Your comfort and fit may differ.
FirmTech says one size fits 95% of men, up to 5.5 inches (14 cm) erect girth, and the hook-and-loop strap adjusts to your exact size. That applies to the TechRing, Performance Ring and MaxPR. If the TechRing does not fit, you are covered by FirmTech’s 30-day risk-free trial.
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 girth is 5.5 inches (14 cm) or less, FirmTech’s rings fit. The TechRing Guide size chart page includes a quick fit checker that also converts centimeters to inches.
FirmTech rings come in one adjustable size rather than numbered sizes. The chart is simple: an erect girth up to 5.5 inches (14 cm) is within the fit range for all three rings, and above that the rings are outside FirmTech’s stated range. Within the range, the strap lets you set your own tension.
The MaxPR is FirmTech’s tightest ring, rated 5 of 5 for tightness. It is slimmer and snugger than the Performance Ring, built for maximum firmness and a more intense finish, and is worn for up to 90 minutes at a time. The TechRing and Performance Ring are each rated 3 of 5.
Yes. FirmTech’s rings are designed to go on when you are soft, so you can put one on discreetly ahead of time. Loop it behind the testicles and around the base of the penis, fasten it snug but not tight, then fine-tune the tension until it is comfortable.
Yes. FirmTech offers a 30-day money-back guarantee. You can start a return online through its returns portal with your order number and email, or contact customer service. The TechRing carries a 1-year warranty, and the Performance Ring, MaxPR and RingMate each carry a 3-month warranty.
FirmTech's team answers product, sizing and HSA/FSA questions by email.