The Grille
Early Rogers LS3/5As used a brown cloth material. But the vast majority of LS3/5As manufactured used black Tygan grilles.
The LS3/5A grille frame is made from a piece of 1/4″ (6mm) 5-layer Birch Plywood with Tygan stretched over it and stapled at the back When subjected to heat the Tygan shrinks tightening up the grille.
The material specified for the LS3/5A grilles is Tygan a woven thermo-plastic monofilament which was developed in the USA but manufactured in the UK by Fothergill and Harvey in Manchester. Tygan is no longer manufactured and the only sources are from surplus stock. The manufacturers described it as having low sound absorbtion and impervious to water, oil, most acids, dirt and moths! Apart from loudspeaker grilles the best known application for Tygan was deck chairs, but other uses included car seats and blinds.
The LS3/5A is balanced for use with the Tygan grille in place. The grille is attached to the baffle with Velcro and pulls off, although it may be quite difficult to remove. Don’t use a screwdriver or other metal object as a lever because you may damage the veneer on the edge of the cabinet, instead use something like an old plastic credit card.