Let me start by saying this set does EXACTLY what it claims when it comes to cleaning. The plastic brush is stiff enough to scrape off years of grime from my window unit's coils without feeling flimsy. I could immediately feel the difference in airflow after just one pass - my AC sounded less strained!

The metal fin comb, however, was a different story. Like other reviewers, I struggled with bent fins. The tool feels sturdy in hand (almost too sturdy), but trying to straighten fins felt like performing surgery blindfolded. I definitely needed bandaids afterward - those fins are sharper than they look!

Where this kit shines: The brush makes routine maintenance a 5-minute job. I keep it with my seasonal supplies and give my units a quick scrub during spring prep. But if you're expecting miracle repairs for badly damaged fins, temper your expectations.

Pro tip: Wear gloves when using the metal comb, and go slower than you think you need to. The plastic brush alone might be worth the price if you're mainly doing preventative cleaning rather than major repairs.