Physics toolbar, Domains, Coil

Hi,

I am trying to model a loudspeaker driver, according to a tuturiol https://www.comsol.com/model/loudspeaker-driver-1369 And at page 20 I need to choose 'Coil' in the 'Physics' toolbar in the 'Domains'. I cannot select 'Coil', the only options appearing is: - Amperes law - Velocity (Lorentz Forces) - External Current density - Initial Values

Hope someone can help me out.

Kind Regards,

Tom