The purpose of a vasectomy is to prevent the delivery of sperms during intercourse. The vas deferens is a narrow duct that carries sperms from the testicles to the point of delivery. The surgeon locates the vas in the scrotum and then blocks sperm delivery by tying the tiny vas tube and cauterizing it. This blockage prevents sperms from leaving the body. Fingers are used to gently locate the vas under the skin in the upper portion of the scrotum. In the open-ended no scalpel vasectomy, the end attached to the testicle is left open, serving as a "venting system" thus decreasing the chances for backup pressure and persistent pain. Local anesthetic is injected to numb the skin and the vas area, causing a sensation that most patients describe as similar to a small mosquito bite. Numbing is achieved within 10 seconds. Very little, if any, discomfort is felt while making a tiny puncture in the scrotum. Using a small surgical instrument, the vas is then gently drawn out through the puncture, divided and tied off on the abdominal end. No stitches are needed to close the small puncture.