The 1.5mm length is the one that I use for my squishy little paw and most of my other squishes, for the Giant paw and pillow I use 3mm length flocking, and for the huge bear&paw I use 0.8mm cuz this version is finer and more like snow shape.
It's not fiber glass, it's flocking powder in different length which made of nylon material, so please don't worry you can definitely play around with hands. BUT, it's still not edible so please keep it away from pets or kids.
Tho I highly recommend play within the bag, but just in case you prefer to take it out, please wash your hands after. I hope this info helps and enjoy your day!
