31 EXTENDED SURFACE ELEMENTS MADE OF PLASTIC USEFUL AS CONTACT MEDIA IN APPARATUS AND INSTALLATIONS SUCH AS BIOLOGICAL OXIDATION INSTALLATIONS, GASLIQUID CONTACT SYSTEMS, AND THE LIKE
FIRST USE JULY 31, 1954; IN COMMERCE MAY 26, 1955; PRIOR TO 1895 AS TO THE TRADEMARK "DOW" FIRST USE JULY 31, 1954; IN COMMERCE MAY 26, 1955; PRIOR TO 1895 AS TO THE TRADEMARK "DOW"