These bibs are amazing. It is a sort of apron and protects the clothes of your baby or toddler.
And the reason for the double layer of fabric at the bottom? That has been thought through! While eating autonomously, your child will often let food drip along his chin, onto the bib. The bottom edge of the bib will collect these blobs and pieces. A drip tray, so to speak! That is something you will value!
The liquid and blobs at the front will not leak through onto the clothing. This because of the waterproof material that this bib was made of.
You close the waterproof bib by use of Velcro on the back. That will remain in place so your baby won't be able to easily pull of the bib himself. The bib can be wiped with a moist cloth. Are there many slop moments during a day? Then buy a duo-pack. Then you have two similar bib aprons in one purchase.