Engineering Reference Credit Card

This card features an 8 cm ruler and 4 different-sized circles. I designed this model because I found it very hard to model without a ruler next to me for scale. But carrying around a ruler is a bit inconvenient, so I design a tool that accomplishes the same task as the ruler and is the same dimensions as a standard credit card. Please like and share. If you would like me to add other features to the card please leave a comment and I will try to implement it.