I use the 3M wiring marker tape in the little red dispenser that costs almost $50 (go figure)local electrical supply will have them too, probably cheaper too

3M ScotchCode Wire Marker Tape Dispenser w/ Tape STD-0-9, Includes 1 each of 0-9 numbered rolls
Buy 3M ScotchCode Wire Marker Tape Dispenser w/ Tape STD-0-9, Includes 1 each of 0-9 numbered rolls at Amazon. Customer reviews and photos may be available to help you make the right purchase decision!
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It's handy but, I would never pay that much for one. I've had mine for so long I don't remember what it cost.