Compatibility depends mainly on the punch pitch, hole shape, coil diameter, and inserting capacity of the equipment. Most standard plastic coils use a 4:1 pitch, which means four holes per inch, but other pitch patterns are also available. A 4:1 coil should only be used with paper punched to the same pattern. The machine must also support the selected coil diameter, particularly for thick documents. Some equipment can punch and insert coils, while simpler machines require the coil to be inserted by hand. Confirm the machine specifications before ordering supplies, especially when working with large diameters or non-standard document lengths. Colour does not affect compatibility, so neon red coils perform in the same way as another coil of the same pitch, diameter, length, and material.