Sizing Guide
Measure Twice, Order Once
To ensure a precise and comfortable fit, it is important to take accurate measurements. Please follow these guidelines
If you would prefer an easier way to measure, we offer a full sizing kit that includes rings, tubes and a shaft length tool. If you have your own 3d printer, the STLs fro all the sizing pieces are available at https://makerworld.com/en/@hzdgrip
Measure carefully The sizing kit is your best option for correct measurements. If you don't want the sizing kit, use a flexible measuring tape, calipers, or a piece of string for the most precise results. There are 2 basic measurements that are needed and 2 optional measurements available with custom devices.
- Shaft Diameter
- Glans Ring Diameter
- Shaft Length (Optional)
- Glans Length (Custom Only)
A few helpful tips before you begin
✔ Take multiple measurements at different times of the day to account for natural fluctuations.
✔ Do not pull or stretch the penis while measuring—keep it in its natural resting state.
✔ Ensure a snug but not tight fit when wrapping the measuring tape or string around the shaft.
✔ Do not base your measurements on other devices or measurements used for other devices. The Grip is unique in its design and other styles of measuring may not provide a proper fit.
All Measurements are based on flaccid states
Measuring the Shaft Diameter
This measurement ensures the shaft cage fits securely around your shaft without being too tight or too loose. You want the shaft cage to be somewhat fitted. It should not be so tight that you need any lubrication to put it on.
It's a little harder with the o-rings, but they will get you close.
If you are an extreme grower you may find sizing up one or two millimeters to be beneficial. It may also be helpful to measure both flaccid and erect. The shaft size should fall somewhere between your flaccid size and erect size. In general it should be within 1 or 2mm of your flaccid size
Method 1: Sizing Rings or O-Rings (Preferred)
For the shaft, you want the o-ring that is snug but not overly compressing. You don't want it loose or to have room where it just slides on and off with no effort. You also don't want it clamping down and creating an indention on your shaft. When you have a ring that you need to pull on, won't fall off when you let go and isn't squeezing your shaft, then you are probably at the correct size.
Method 2: Using a Measuring Tape (Not recommended)
- Ensure your penis is fully flaccid.
- Wrap a flexible measuring tape around the middle of the shaft to get the circumference.
- Record the circumference in millimeters (mm) or inches. You want the measurement to be snug without compressing the shaft
- Calculate the diameter by dividing the circumference by π (3.14).
- Round to the nearest whole number
- Example: If your circumference is 100mm, your diameter is 100 ÷ 3.14 = 31.8mm. Rounded up to 32mm
Method 3: Using a String (Not recommended)
- Ensure your penis is fully flaccid.
- Take a piece of non-stretchable string or thin strip of paper.
- Wrap it around the middle of the shaft where the measurement is needed.
- Mark the point where the string overlaps itself.
- Lay the string flat and use a ruler to measure the length from the start to the marked point. This is the circumference
- Calculate the diameter by dividing the circumference by π (3.14).
- Round to the nearest whole number
Example: If your circumference is 100mm, your diameter is 100 ÷ 3.14 = 31.8mm. Rounded up to 32mm
Measuring the Glans Ring Diameter
This measurement ensures the glans ring holds securely without being too tight or too loose. There are limits to how big the glans ring can be in comparison to the shaft. The Glans Grip needs to be less than 82% of the shaft diameter
Method 1: Sizing Rings or O-Rings (Preferred)
For the glans you want a snug fit. If you don't have to pull the glans through the ring with some effort it is probably too big of a ring. If you are using the sizing rings, you can use the small tab to simulate the pressure of the clamp. Place the tab at the bottom of the glans and then pull it forward. If the ring pulls off without too much effort then you are too big. If the ring holds tight and your glans starts to turn towards the ceiling you are pretty close to the correct size.
If you are using an o-ring, you can perform the same test by threading a piece of string through the o-ring. move the string to the bottom of the glans and pull forward. If the ring pulls off without too much effort then you are too big. If the ring holds tight and your glans starts to turn towards the ceiling you are pretty close to the correct size.
Method 2: Using a Measuring Tape (Not recommended)
- Locate the area directly behind the glans (where the shaft meets the head).
- Wrap the measuring tape around this area or use calipers to measure across.
- Record the circumference and divide by π (3.14) to find the diameter.
- Round up to the nearest whole number
Example: If the circumference is 90mm, the diameter is 90 ÷ 3.14 = 28.6mm. Rounded up to 29mm
Method 3: Using a String (Not recommended)
- Wrap a piece of string around the area immediately behind the glans.
- Mark where the string overlaps.
- Measure the length of the string with a ruler.
- Record the circumference and divide by π (3.14) to find the diameter.
- Round up to the nearest whole number
Example: If the circumference is 90mm, the diameter is 90 ÷ 3.14 = 28.6mm. Rounded up to 29mm
Measuring the Shaft Length (Excluding the Glans)
Any length longer than a size 1 is 95% cosmetic. There is no significant security benefit to the longer shaft.
Too short is better than too long. Too long of a shaft cage will cause undue pressure on the glans and could cause irritation. Too long of a measurement can also compromise security. The grip works similar to a finger cuff. If the shaft is so long that it provides slight constant pressure against the glans, it is harder for the grip to be activated and create the clamping pressure needed.
Using the Length Guid included with the Sizing Rings
The sizing rings include a guide for measuring your length along the bottom of the shaft. Place the guide under your shaft. Looking down from above, choose the number that matches the point where your glans starts. The base end of the guide (starting at size 1) should be placed against the scrotum. The length guide should not be pushed into the scrotum; it should just lightly touch it. The shaft of the penis should lie on the guide itself. If you are between two numbers, pick the smaller of the two. Use the number to select your size when ordering your device. In the example below, the selected size would be 3.
Along the bottom
- Ensure your penis is fully flaccid.
- Place a ruler or measuring tape along the bottom of the shaft, starting where the shaft meets the scrotum.
- Measure only the shaft length, stopping where the shaft meets the glans (do not include the glans itself).
- Round this number to the nearest whole number.
Length Size
| Size | Length Range |
| 1 | < 40mm |
| 2 | 41-44mm |
| 3 | 45-48mm |
| 4 | 49-52mm |
| 5 | 53-56mm |
| 6 | > 56mm |
Measuring the Glans (Custom Only)
The glans measurement can be customized on the custom nylon product. By default the glans length is 90% of the shaft diameter. On the custom nylon product, this can be shortened or lengthened. The short version will be 4mm shorter than standard and the long version is 4mm longer than standard. For the glans hood, longer is better than shorter for comfort. Too short of a glans hood will cause the glans to always push backwards into the glans ring and will make the shaft more prone to hotspots.
This measurement is measured along the side of the glans along the center line of the shaft. It should fall in the middle of the glans.
For any questions regarding measurements or fit, please contact our support team at support@headzonedefense.com