Taking the measurements for your cage is a very important stage, and must be treated with patience and care:

- A cage that is too large will, contrary to what you may think, be a less comfortable one. It can slip forward, pulling annoyingly at the base ring and testicles, and can also take up excess room under close-fitting clothing like jeans, resulting in much fiddling and readjustment.

- A cage that is too small can cause painful tightness, gradual loss of circulation or even eventual injury, meaning you will likely spend more time recovering than being able to wear it. This may not be a deal-breaker over short period of time, but for those interested in long-term or 24/7 wear, it pays dividends to ensure a more comfortable fit.

Like for everything in life, the game will be to find the right balance between the all possibilities.

The 4 main measurements to determinate the size of your future chastity device.

- Measurement 1 (Penis diameter): Be seated on a chair and allow your penis to rest naturally between your thighs. Measure the width of the flaccid penis, taking your measurement from the shaft rather than the glans. This will give the diameter to use for the tube.

- Measurement 2 (penis length): Important: Make sure you measure when you are at total rest! We know how easy it sometimes is for the male body to be excited by probing hands, but you must not perform your measurements with even the slightest hint of an erection! Stand up straight, hold your penis horizontally in one palm and measure from the base of the penis – where it meets your body – to the tip of the head or glans. If you have a foreskin, this measurement should remain the same; do not measure to the tip of the foreskin.

The position of the penis can greatly influence your measurements. The effect of gravity will change your length measurement. In this example, we can see the different in result from each position: if we point the penis upward, it measures 60mm; if we hold it perpendicular to the body, it measures 80mm; and if we let it hang downward, it measures 100mm. These are sizeable differences! The correct value to determine tube length is the average measurement with the penis perpendicular to the body: 80mm.

Next, to determine the overall tube length to order, it is necessary to take this number and subtract two others from it: the base ring thickness (about 6mm) and the gap between the base ring and tube (about 10mm). For a penis measuring 80mm in length, therefore, you would calculate 80-10- 6= 64mm for the perfect tube

A simpler calculation, that being “Penis Length-20mm”, can work effectively as well. For a penis length of 80mm, a 60mm tube will be a good fit.

Beware: This work with a tube diameter equal at your penis. If you use a tube diameter 5 mm over your normal size, you can reduce the tube length even more, until 15 mm. The penis accepts very well to be compressed in length, if it has enough space in diameter. At contrary it doesn't accepts to be in a too small diameter, and can suffer wounds.

Example: I have a 90mm penis length at rest with a 35mm diameter. I normally will use a (90-20)70x35mm chastity tube then. If I use a bigger diameter as 40mm, I can reduce the tube length to 50/55mm, and the cage will fit good, allowing long last periods, even with the penis forced in length. The bigger diameter will let some space for the forced penis.

At building, we determinate the tube's length, measuring the central axis.

- Measurement 3 (Base ring diameter estimation): Often the most difficult to define, this may require several tries; The deal is to find the best compromise holding/comfort. Some can get an approximate result by tying a piece of string – not something elasticated – around the base of the penis and testicles, in order to measure its circumference. I don't like this beta at all, because it too often gives numerous of mistakes. A 2mm difference can change completely your feelings. Our better advise is to purchase sizing rings to try on before ordering. It's finally the best solution, we often advice this website where you can try for few euros, the same stainless steel rings as we use (6x40; 6x45; 6x50 for base rings and 4x25; 4x30; 4x35; 4x40 as we use for the tubes).

Here a 45 mm ergonomic base ring - The most common combination.

- Measurement 4 (Gap estimation): The space between the base ring and tube is rather difficult to measure precisely, and may be down to guesswork. Generally, the 8-11mm range works for the majority of customers. This value is connected to the shape of your testicles, and the important goal is to prevent escape, so any value over 15mm we feel is excessive.

We advise to choose the biggest gap you can take without having issues with the testicles "poping-out". A too thin gap can cause injuries!

Last advise:

- Measurements should be accurately performed, and we recommend repeating them a few times over the course of the day and calculating the average result.

If your exact penis length does not match any of the values in our guideline table, choose the next value down in size. When in doubt, it is generally better to err on the smaller side than the larger one. A cage that is slightly too tight will still be comfier than one that is slightly too large. If the guideline values are very different from your size, please let us know and we're confident that we can find a solution for you.

- If your penis diameter is between two standard sizes, choose the size over (at the contrary concerning the penis length). For example, if you are between 30 and 35, choose 35 and reduce the tube length a little bit.


Do keep in mind that, as each body is different, the only way to be certain of the best fit is by trying on a device itself. Our guideline values have been calculated to help you reach your most comfortable fit with the minimum of trial and error.

Take care with the sizing, Mistress needs a perfect control on your sex!