My Oster Blender is about 20 years old, and essential pieces had worn down. The blender wasn't able to "blend" as it should. There were several "chunks" in the mix. The new pieces solved that problem. My only suggestion would be to include some instructions with the parts. I found some instructions online, but needed to go to the local hardware store to find what I needed to open the base, as none of my screwdrivers worked. Turns out I needed a #2 Craftsman Phillips Screwdriver to open the base, and now all is working like new. I hope the blender works another 20 years!