Vintage 8'in fresnel lens for photo studio work or industrial task lights

Mid-century, machine-age vintage, 8'' round glass bulls eye fresnel lens for use as replacement parts in studio task lights or theater lamps, like the Mole-Richardson Solarspot lights. This fresnel lens is marked "Silver-litecraft Corp, Passaic, New Jersey", "Pyrex" and is marked 8-3/8 inches. It measure 8-3/8" in diameter (across) and about 3/8" thick overall. This lens is in excellent condition.