Holy Trainer Sizing Advice
Selecting the sheath size
There are two sizes of tubes (also called "sheath"): measuring from the bottom of the tube to the end, the length of the "Standard" model is 60mm (2.35inch); the Small model is 48mm (1.9inch). When selecting an appropriate size for yourself, you should base your selection on the distance of the underside of your flaccid shaft from the tip of the head to the end where it meets the scrotum. Do not stretch the shaft out in any way when taking the measurement.
The inside diameters of the Standard and Small sheaths are 35mm (1.4inch) and 34mm (1.3inch), respectively.
Selecting the ring size
If you have worn a CB-X product, the largest ring (2") or next largest (1-7/8") with one of the larger spacers, will normally be equivalent to a 50mm ring on Holy Trainer. The next largest (1-7/8") if used with one of the smaller two spacers, or the 1-3/4" ring with large spacers would be most closely equivalent to the 45mm. Otherwise, the 1-3/4" ring would actually be more equivalent to the 40mm ring. The 1-5/8" ring usually equates to the 36mm ring size on the Holy Trainer.
Most men would use a ring with a 45-mm diameter. However, other diameters are available. The following is a 4-step procedure suggested by the manufacturer to help you determine the right diameter for you.