External Catheters are sheaths that fit over the skin to drain the bladder. The most common type is the self-adhesive catheter. The catheter sheath has a skin-friendly adhesive which, when rolled onto the skin, forms a seal to prevent leakage. The tip of the sheath is connected to urinary tubing which leads to a urinary leg bag or other urinary catheter drainage bag. External catheters usually may be worn for up to 24 hours. Both all silicone and latex catheters are available. Both are good options, but more men prefer the all silicone. A variety of sizes is available for each type. Measuring guides are available, but a good guess and initial purchase of only a few of a couple of sizes should lead to a good outcome. If the catheter is too tight, it may pop off. If it is too loose, it may leak.