Use the following guide to select the proper
Chimney Brush for your chimney.
Measure the inner
opening (both directions) of your fireplace or woodstove chimney.
For masonry chimneys you'll need to measure the inner opening dimensions in both directions. Buy a brush that is at least as big as your chimney liner otherwise it will not reach the side walls of your chimney and won't do an adequate job. If you buy a chimney brush that is too big then it will be harder to get down the chimney but will work unless excessively oversized.