i tried to print with numbers but it was too small, and i already printed it, so i didn't want to change, i removed the numbers from final model, but the model starts at 0.2mm into 10mm. 

so you can see and show people which wall, or base you want to work with. so you can feel it. 

the middle is exact 5mm. 

in the picture you will see 0.5mm on the first, but it was a mistake on my slicer as i by mistake made it do one extra contour, making a small wall on the side, but it's 0.2 mm. also hard to take pictures with two hands and the caliper at same time haha.