Motorcycle Chain Slack Ruler

I was doing a chain maintenance on my bike and I wanted to verify the slack size, which obviously can be done just using a simple ruler, but it is susceptible to measurement inaccuracies due to visual parallax errors. So I decided to create a bike chain slack ruler. It takes like 40min to print and it's very easy to use. Here are the steps: Put the ruler over the swingarm and in the middle of the sprockets. Leave the two moving tabs of the ruler below the chain Then lift the chain with your finger or any tool (like a screwdriver) and lift the top tab until it touches the chain Then, take out the ruler and leave the chain in it's initial position. Then insert again the ruler making sure the top tab is above the chain and the bottom tab is below the chain Then press the bottom tab until it touches the chain. Make sure you are not lifting the chain. Now you can take the ruler out and you'll have the chain slack. You can use the ruler lines to measure it (each line gap is 5mm)