Round

MULTIPURPOSE – Great for large glass jars, tall vases, carboys, gallon jugs, Hummingbird feeder, tea pots, tumblers, thermos, especially the long narrow neck ones. HOW TO CLEAN THE BOTTOM OF A BOTTLE- The brush head is bendable, to get much more bristles, bend the brush head by hand or with pliers, you can get a brush with a righ angle head to clean the bottom of the bottle.