The present disclosure relates to monocationic monochromophoric compounds of formula and and dyeing compositions and multicompartment devices comprising monocationic monochromophoric compounds of formula and. In an aspect of some such tools, a video message from the calling party is sent to the receiving party through a communication channel in the provider network. The pipe comprises two sensors transversely to the longitudinal axis thereof, said sensors being located at an angle of substantially 90\xb0 to each other and each being disposed at an angle of \xb145\xb0 to the direction of the shear stress component \u03c4xy.