This capacitor is the direct replacement for many Rheem, Ruud, and Weatherking models. This capacitor replaces Rheem Ruud Weatherking part numbers 43-100509-43, 43-100509-45, 43-101666-43, 43-21298-38, 43-21298-43, 43-21298-45, and 43-24136-08.IMPORTANT NOTE ON CAPACITOR FITMENT:This is a round capacitor which measures 1-3/4" in diameter at the base. If your capacitor measures 2" in diameter at the base, this IS NOT the correct capacitor for your unit.Due to changes in capacitor materials and manufacturing over the years there have been slight variations in case diameter. This is especially true if replacing an older plastic capacitor with a new metal case capacitor. If your capacitor mounts through a round hole bracket it may be necessary to enlarge the hole slightly with a file or grinder on some older units.