The other, which has a small valve on the end, runs inside the main tube and is connected to the inflatable balloon at the tip. One is operated by a hypodermic syringe without a needle. A third type has a bulb already filled with sterile water for inflating the balloon, and a clamp to enable the water to flow. Sterility O nly factory-sterilized catheters should be used. Avoid the temptation to try to sterilize a used catheter.
Some states require a prescription for catheter purchase.
In buying a Foley catheter, you must describe it by both of these dimensions. Like some other medical items, catheters are sized in the French system. Most adult males can easily handle a 14Fr, and 16Fr or 18Fr is very common. I recommend 30ml for reasons which will be made clear below. If you intend to take total control of the bladder, a sterile catheter syringe.