It's very hard to make a mistakes when you draw a line with this pen,unless someone push your hand.LOL. It glides smoootthhllyy on my eyelid,unlike any other liquid liner that doesn't mistake proof. It's pretty cheap for the quality,it long lasting but unfortunately it's not waterproof/water resistant...It smudge/smears after I yawned (>o<) haha. It's not for watery eyes like me, but I really like this pen liner, extremely easy to apply, dry quickly. I hope they will make the waterproof version of this,huhuh.