This 3" X 4" filter with a 1 1/8" opening fits the Animal and all the OEM 206 CC carbs. It has been used since the first Briggs OHV engines were introduced. However, It is not legal for us at many tracks and events. As with any kart racing engine it is highly recommended to spray it with a good name brand filter oil and for additional protection add a nylon Outer wears pre filter. It's a great filter if you are not required to run a #555729 Briggs filter!