The Akrapovic Optional Stainless Header Pipe E-H125R3, when paired with the Twin Conical Stainless Exhaust Slip-On Kit S-H125SO5-FFT, provides the capability to upgrade to a full system. Outfit your ride with increased power, superior styling, and the legendary Akrapovic sound. This set is certified for use only on closed-course circuits; it does not meet emissions standards for public roads or highways. Compatibility This header set is compatible with the following motorcycle models: Honda Monkey 125 (4-Speed) 2018-2021 Honda Monkey 125 (5-Speed) 2021-2023 Performance Data Unit Stock Akrapovic Max gain Max. power kW 6.8 / 6750 rpm 7.4 / 6700 rpm + 0.6 / 6700 rpm HP (m) 9.2 / 6750 rpm 10 / 6700 rpm + 0.8 / 6700 rpm HP (i) 9.1 / 6750 rpm 9.9 / 6700 rpm + 0.8 / 6700 rpm Max. torque Nm 11.7 / 4400 rpm 12.1 / 4350 rpm + 0.8 / 3700 rpm lb-ft 8.6 / 4400 rpm 8.9 / 4350 rpm + 0.6 / 3700 rpm Weight kg 4.8 2.7 - 2.1 lb 10.6 6 - 4.6 % - 43.8 Product noise dB 78 / 3500 rpm 88.3 / 3500 rpm 10.3 Inst. time min 45