If $tau_1$, ..., $tau_n$ denote numbers, then the term {tt (* $tau_1 ldots tau_n$)} denotes the product of those numbers.
and also:
Q* is the nary q-operator for expressing the multiplication productof its q-expressions arguments.
Eg: (Q* (Term-12 current) (Resistor-13 resistance)
(Undefined (Arity *)) (Undefined (Arity *)) (Undefined (Arity *)) (Undefined (Arity *))