Dont miss this deal! The nylon ring on these ensures that they dont back off the axle wile your on the track! They also dont crack like the cheapo plastic ones that come with the xmod kit do! they screw on far so that you drastically reduce wheel wobble! this increases torque, and top end. By reducing this wheel wobble, you car will run much smoother and faster. Also the reduced friction helps your motor lasst longer and prolongs battery life! Many good points for such a little, inexpensive item! i recommend combining these with aluminum wheels! they look great! The finish is durable and i have used these for a while and am on only my second set. Thanks rcmart!