These are made for the two middle steps in the IKEA MYDAL bunk bed, so you don't hurt your feet when climbing up. Sized to fit in a standard printer.
The first and last steps are actually wider and I found we didn't actually use those to climb up the bed. So these are only made for the two middle ones.
I suggest printing these with a minimum 40% infill. We printed these with PET-G and can hold up an 80kg adult without cracking.