The NutriBullet range of blenders has one great advantage; almost all its parts can be replaced including the top gear of the base. The replacements for the top part of base are in sets of four offering you more value for your money. Aside from this, the replacement top gear part of the base can fit on any model of the NutriBullet blenders even the NutriBullet Pro and NutriBullet Classic models. The top part of the base are reverse threaded for a tighter fit but also allow for simple fitting in place just atop the power base. The threads are strong enough to prevent wearing out over time, are made of sturdy plastic matching the rest of the blender in terms of durability. The top part of base for your NutriBullet is also leak proof ensuring no spills of the blended material. Aside from matching the design of all NutriBullet blenders, the design of the top gears allows for easy cleaning and maintenance. This is a quality replacement gear spare for the world class NutriBullet blending system.