Size Guide - Viper Cages

Coming from Cobra? Read this first!

Viper features a new shape with a more consistent inner diameter than Cobra. Viper doesn't have the wide entrance, narrow "neck", and flared head of most Cobra sizes. This means, in general, Viper has more space in the middle area of the cage, and less space in the head.

As a result, Viper can work a bit differently from Cobra. Viper isn't designed to lock the head of the penis in place. Rather, it is normal with Viper for the head of the penis to fit partly inside and partly outside the head section of the cage. This lets the penis slide back and forth more easily as it naturally changes shape throughout the day.

For fans of our Wide versions, please note that Viper cages in Wide maintain their extra width for the entire length of the cage. This means they are truly large — especially in the R length and above. It may be helpful to compare the specifications for Viper and Cobra to get a better sense for what size will serve you best.

Sizing Overview

When measuring flaccid length, allow the penis to hang naturally. Measure along the top side of the penis from base (where it meets the body) to tip.

It's best to use a ruler, a cloth tape measure, or a string (which you can then measure).

We suggest measuring several times over the course of the day under "normal" conditions — not right after a hot shower, and not when it's extremely cold. The goal is to find your typical smallest flaccid length, rather than the absolute smallest you ever get.

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The advice on this page is a best guess, but everyone's anatomy is different. It is not a guarantee.

New to chastity and/or Viper cages? We highly encourage you to seek sizing advice before ordering. You can email us directly or ask the community on Reddit at r/kink3d (NSFW).

Length Advice

In our experience, customers are happiest when their Viper cage is a good match for their flaccid length. If the cage is too short, it can hang away from the body and only partially cover the penis. If the cage is too long, the head of the penis may not sit towards the tip of the cage.

Getting a new chastity cage can be exciting, and we're all about that! However, please make sure you aren't partially aroused when you take your measurements. You don't want to overestimate your true size.

If you're on the border between two sizes, in our experience, most people prefer going with the shorter size.

Width Advice

We've found that the Standard width works well for most people.

If you have a thinner than average penis, or you've found that chastity devices are often loose on you, a Narrow width might be a good choice.

On the other hand, if you have a thick penis or have had trouble fitting into other devices in the past, the Wide option may be good to consider. Wide cages can be particularly helpful for certain uncut customers, to avoid squeezing down on the foreskin, though this is by no means universal.

Learn More

For chastity experts, detailed cage measurements are available on our Viper and Cobra specifications pages.

For help with base ring sizing, please refer to our KINK3D base ring sizing guide.

And for lots more helpful information, don't forget about our searchable FAQ.