A knitting needle cap, also known as a point protector, is a cover placed on the tip of a knitting needle that is being used for a project that is resting. The cap prevents stitches from coming off the ends of needles.
There are knitting needle caps for both one and two needles. Those made for one needle look similar to erasers that are attached to the ends of pencils. Those for two needles are wide and flat with two holes.