Titanium countersunk screws to attach your Sonar Carbon Fuselage to your Sonar Mast. The Sonar Carbon Fuselage Screw Pack B2 (M8x30 TH CSK T40) is designed to fit Sonar Carbon Fuselage with tapered countersink holes. How to identify the correct screws for your carbon fuselage: Some Sonar Carbon Fuselage will have tapered countersink holes. These allow the head of a flathead screw to sit flush with the top of the fuselage. Tapered holes = Screw Pack B2. If your carbon fuselage has tapered holes (similar to your Sonar front wing) you will require the Sonar Fuselage Screw Pack B2 (M8x30 TH CSK T40 - 85009.240145). Straight holes = Screw Pack B. Some earlier models of the Sonar Carbon Fuselage do not have countersink holes, so will require Sonar Fuselage Pack B (M8x35 THCS T40 with M8 Washer - 85009.200136).