Spacers with Numbers - 1, 2, 5 mm

5 mm spacer with number for Simple PET Bottle Cutter. I created a 5 mm spacer just to print these spacers:

• 2x 1 mm
• 2x 2 mm
• 2x 5 mm
• 2x 8 mm

(two of each because you need spacers on both sides) and then by combining these spacers I can cut strips with widths of:

• 5 mm
• 6 mm
• 7 mm
• 8 mm
• 9 mm
• 10 mm
• 11 mm 

The advantage of having this combination of spacer pieces is that different strip widths are needed for different PET bottle thicknesses.
I attach here a table from @Koddra on what width to use for different PET bottle thicknesses.

The best way to print accurate spacers is to use adaptive layers.