Product review (5 stars): so far so good. There are videos on youtube about how to ...
Perfectly fit my kenmore 700 series electric dryer and eliminated this awful squeaking problem during the first few minutes of operation. The drum was noticeably easier to turn afterwards. Nearly 2 months later, so far so good. There are videos on youtube about how to open and swap out the pulley. Not too hard, just remember to wear thick gloves or cut-resistant gloves as the sheet metal inside is really sharp! As a bonus, I ended up vacuuming nearly 10 years worth of lint from the exhaust and the bottom of the dryer, so now it nearly looks new.  My only regret was not buying the inexpensive replacement rollers so that I could renew all the major wearable items while I had it open.