Having a CR-10 Smart at home and at work, I kept forgetting which nozzle size was in which printer, so I made these to sit on the top of the printer in the groove of the top rail.
Used a little paint on the numbers to make them stand out. Indicators face away from front of printer, except for the one for the nozzle size that's in use. Decimal is only on the 1.0 size.
The author hasn't provided the model origin yet.