Additional lower lengths are available to help in finding the perfect fit, or for use with multiple players. 

Sizing:

Internal diameter (40mm or 50mm): The size refers to the internal diameter of the lower section. 40mm is by far the standard size.  Choose a size equivalent to your erect diameter – up to 5mm smaller is ok Diameter is calculated by dividing circumference by 3.142 (π)

The length of the lower cylinder can also be chosen as this governs how much of the penis is in the upper chamber – and so in contact with the e-stim liquid.

Length:

This length is the distance from the cylinder base to the top of the polished acrylic separator. So measure the erect penis length to the groove around the base of the glans. This will result in the glans being in the fluid chamber. To have more of the penis in the fluid chamber choose a shorter length.