The FMF muffler plug is a great way to keep dirt and debris out of your exhaust while in storage or traveling. Use when washing your ATV or Motorcycle to keep water out of your exhaust system. 4-Stroke model has tapered rings spanning from 0.95" to 2.0". 2-Stroke model has tapered rings spanning from 0.525" to 1.15". Remember to remove the FMF muffler plug from your ATV or motorcycle before flight! Notes: Check measurements before ordering. Wash plug cannot be used with some spark arrestor / quiet inserts. Please remove inserts before using washplug.