In addition to size, there are two kinds of diaphragms: a flat ring option and an arcing or coil spring option.
Designed to fit securely in the vagina to cover the cervix, the diaphragm becomes a barrier that blocks the opening to the uterus. Diaphragms must be used with a spermicide (like Gynol) as this additional birth control method hinders sperm movement. Diaphragm use includes needing to be inserted before sex (no more than 6 hours ahead of time), and it should be left for 6 to 8 hours after ejaculation. It is important that you practice inserting your diaphragm – as you want to increase your diaphragm use success.