First choose the right size brush. The inner dimensions of your chimney flue should match the brush size.
Wire or Poly? Chimney pipe manufacturers recommend the use of Poly brushes (plastic bristles) to reduce scratching and wearing of the inside of a metal chimney.
Now choose a type of brush that fits your needs and budget.
Light-Duty - Infrequent use, easier to get down chimneys with heavy creosote build-up or bends in the chimney, requires more work.
Medium-Duty - Easier to get the brush down the chimney with thick creosote deposits or for chimneys with bends than heavy-duty brushes, cleans easier than light duty.
Heavy-Duty - Heavy duty brush bristles and about 4 times as many as light-duty brushes. Requires less work than medium-or light-duty brushes, lasts longer.
Torque Lock Connector - Provides a fast, positive locking connection to the TLC rods. More expensive but when you're on the roof the connections become more important plus the brush won't accidentally unscrew.
Flat Wire - Best choice when heavy scraping is needed. Glaze creosote is very difficult to get off. Use Stage Three Creosote Remover and a flat wire brush.