Each Double Pointed Needle Tube is wide enough to hold five US 10 (6mm) needles (or many more smaller needles or 2 to 4 larger needles). The Tubes can extend to hold 10" long needles, and they shorten to a total length of 6-1/2" for your shorter needles. They have inside diameters of 5/8" and outside diameters of approximately 3/4". 4 Needle Tubes are included in each package.
The needle sizes can be written on the yellow cap (or tube body) with a Sharpie brand marker.