RS-2:. The RS-2 Series has a diamond-shape muffler and includes a straight, single-core baffle. Maximized internal volume. USFS-approved 96dB spark arrestor installed.. RS-5:. The RS-5 Series has a trapezoid-shape muffler and includes a straight, single-core baffle. Maximized internal volume. USFS-approved 96dB spark arrestor installed. RS-2 Muffler Options: . Aluminum sleeve with stainless steel end-cap. Titanium sleeve with stainless steel end-cap. RS-5 Muffler Option:. Aluminum sleeve with stainless end-cap. Slip-on RS-5, Slip-On, Aluminum