Halfshell is a high security chastity device. You will need to have a PA (Prince Albert) piercing for properly using this product.
The device offers highest security by covering the penis in a steel half-shell and keeping it firmly in place by an anti pull out hook. This hook uses Prince lbert piercing (PA piercing) and makes the device 100% secure. There is no way to pull out a penis when the hook keeps it in the cage, The only way to get access to the penis again is unlocking the device or destroying it.
This device has also another very important feature. The secure devices which uses PA piercing usually have movable hooks. If the hook is not solid fixed to the device, it can squeeze or damage skin pinching it between hook and other part of a chastity device. This device will not do this. The hook is in a fixed position and it doesn't change it when the device is locked. No more pinching or damaging the skin.
Halfshell device with PA hook offers highest security. Prevents masturbation and erections as well, giving your keyholder total control. Highest security is not at cost of comfort. It can be worn 24/7/365. The half-open design allows you to keep your penis in good hygiene. The anti-pull-out hook is hidden in the cupola and it will not harm/squeeze foreskin/penis head. The device is hold in place on scrotum ring, so no stress on PA piercing is caused while wearing.
Gauge to mm: http://www.rapidtables.com/calc/wire/swg-to-mm.htm
mm / inch: http://www.metric-conversions.org/length/inches-to-millimeters.htm