We have a size chart you can view here. We strongly recommend that you measure your penis to guide you on what size to go for. Remember that each size adjusts up and down significantly, but getting the right one for you is essential. Give us a call at 1 877 377 2239 if you need some help!We noticed that some of our clients use two sizes to alternate effectively for day and night use. Note, that the adjustable strap of our incontinence product makes it easy to find a perfect fit for your unique penis size and comfort needs during application.