Tools of the trade - Canadian Occupational Safety magazine
Pro-Vents were invented for workers including those in construction and manufacturing jobs who work in environments that get very warm but who cannot wear shorts because of safety requirements. Pro-Vents pants are made from unique poly/cotton fabrics and look like regular, relaxed fit pants. From the knee down they incorporate a polyester athletic mesh that can be covered when necessary using detachable leg covers, but is never removed itself.
ProVents workpants(blog note: click on PRO-VENTS IN ACTION >> for Flash animation)