Screw to the end of the loose
Do you still have to say, it must be the size of the screw and screw. You might as well buy a new one. Generally do not sell a single screw head.
For the sake of insurance or a new bar, add something and then twist, then it is tight, in case of a loose with the use of trouble.
With a soft plastic film on the outer cover of the two or three layer, and then tighten can leak. Spend money to buy, throw a pity.
