SPICE vswitch?

Another question about switches in SPICE:  My SPICE netlist has the
following model line for a switch element:

.MODEL SLATCH1 VSWITCH(ROFF=1E6,RON=500,VOFF=2.1,VON=1.4)

Tclspice reports that the VSWITCH model is not found.  I can't find a
VSWITCH model doing a search on the cannonical SPICE3f5 documentation
site:

http://newton.ex.ac.uk/teaching/CDHW/Electronics2/userguide/index.html#toc

So, is VSWITCH an hspice or PSpice model?  Or is it proper SPICE3f5,
and my head is just wedged?

Stuart