I recommend Oral-B Essential dental floss.

This is the dental floss I use all the time, and I ran out again, so I bought a new one! I highly recommend Oral-B Essential Floss to anyone like me who has narrow, or rather, closely spaced, teeth. Other floss doesn't fit into my teeth, but this one works just fine. The mint scent is refreshing and even better. I recommend using it after or before brushing your teeth. It's even better because it lasts a long time.