Sites ask for "razor wire" and mean two different things. One is a coil that sits on a wall or opens into a barrier. The other is a flat run of razor tape.
Concertina
The coil diameters in stock are 1.5 ft and 2.5 ft. The 1.5 ft coil is the smaller topping. The 2.5 ft coil is the larger barrier. Measure the diameter of the coil as it sits, not the length of tape inside it, when you are matching an existing job.
RBT
Razor barbed tape on this list is 2.5 ft, drawn straight. It is for a straight run, not a sprung coil. If the sample is a tight spiral, order concertina. If it is a flat razor strip, order RBT.
GI only. Line barbed wire in 12, 14 and 16 SWG is the third product in the same family, and it is not a substitute for either coil. Sector 9, Noida. 9910238277.