One embodiment of the invention relates to compounds of the formula I,in which R1, R2, R3, R4, R5 and R6 have the meanings given in the specification. Due to the special design of the gas circulation, the parameters: carrier gas velocity in the GC column, the flow rate of the gas to be analyzed and the flow rate of the drift gas can be varied extensively independently and without reaction. The electrical resistance of the light-shielding substance is 106 \u03a9m or higher, and the substance contains powder of at least one species selected from metals and pigments. The six torque-transmitting mechanisms provide interconnections between various gear members, the fixed interconnections, the input shaft, the output shaft, and the transmission housing, and are operated in combinations of three to establish at least seven forward speed ratios and at least one reverse speed ratio. The slip-coating has a combination of softness and abrasion resistance which are uniquely suited for the purpose of the weatherseal.