Instruct: Classify an Amazon review as either positive or negative.
Query: helps longevity

this base coat is good in that it really DOES help with longer lasting nail polishes. usually with a normal OPI base coat, my nail polish chips within 2 days after 2 layers and an essie top coat. however, this helps it up to 5 days! and if you sandwich it, even without a top coat it lasts for 5 days without chips!to sandwich, you put this stickey base, then a layer of nail polish, then another layer of stickey base, then another layer of nail polish.however i don't usually do that because it takes longer to dry i think. and i like having top coat to make the polish shinier. altho i haven't tried sandwiching AND top coat, so results might be even better!relatively cheap and i've only seen it sold on amazon and salons.One thing is that it does not prevent the yellowing of nails =/