model-specific description: For the Yamaha XJR 1300 Model 2004-2006 (RP10) you can use the Tuning-Kit on it´s own, but for full performance we recommend to use the airducts and the adapter as well, same as for all other XJR models. The Adapter is included the kit because the tuning airducts are a bit shorter than the OEM ones. That´s what the adapter is for. The picture shows kit including needles, for the XJR 1300 2004-2006 the kit is delivered including slider springs instead.