Review on Renew your Oster Blender with Replacement Parts: O Ring Kit, Speed Blade, Jar Base & 2 Gasket Blend Compatible [4961 4902 Blender Parts] by Chad Mills

Fits as written in the description on my Oster mixer that I bought 10 years ago. If size is a concern, this is the one that fits snugly and snugly on a mason jar (not a wide mouth jar, just the regular type). However, one of the reasons I wanted to replace the blade is that liquid would seep through the connections on my old blade - this didn't happen for the first few years after purchasing it, so I was hoping this wouldn't happen with this new part. , but it is so. Come on, at least the blades are sharper (because they're new), don't flow as much as the old ones, and now I have extra spacers.