tubular pin any opening that has a portion slightly larger than the tubular pin to allow a quick expansion of the tubular pin is within the meaning of the u201c enlarged opening u201d for example referring to fig3 the slot may be shaped differently than that shown in fig3 a click sound can be generated if the slot has a narrowed passage 200 202 204 206 208 smaller than the outside diameter of the tubular pin and an enlarged opening 210 212 214 216 218 slightly larger than the outside diameter of the tubular pin the tubular pin is compressed and deformed as it passes through the narrowed passage 200 202 204 206 208 the enlarged opening 210 212 214 216 218 allows the tubular pin to quickly return to its originally non compressed and non deformed position when the tubular pin is received in the enlarged opening 210 212 214 216 218 referring back to fig3 and fig3 the lower housing 160 has a positioning feature for positioning the lower housing 160 relative to the adapting member 194 due to the provision of the protective covers 168 for spoilers the lower housing 160 should be oriented to make the first sides 171 of the protective covers 168 facing away the windshield to perform the wind deflection function the adapting member 194 of fig3 is shown to have a projection 220 provided at one side of the tubular pin 192 when the adapting member 194 is mounted to the lower housing 160 the lower housing 160 must be oriented to have the recess 178 at the same side as the projection 220 therefore the positioning feature that includes.