5 Cup Square Top Glass Blender Replacement Jar for Oster Osterizer 5 cup, square top glass blender jar. Replaces Oster square top glass jars. Fits all Oster blender models using a 5 cup jar with a square top. Fits all Oster Kitchen Center models. This is the most common Oster jar type. All Kitchen Centers use this type of jar. This will fit all Oster blenders, but if your is a VERY old model (40 years old), using a 4 cup jar or a new model using a 6 cup jar, your lid will not fit and you may need to purchase the OS-060 lid and cap. THIS IS NOT A GENUINE OSTER PART. Product Details 5 cup square top glass jar fits most Oster and Osterizers Fits all blenders which use a 5 cup square top jar Square top with opening of 4" X 4" (Interior size) Glass