M-D Building Products 11502 M-D Heavy Duty Fluted Top Door Threshold, 4 in W X 36 in L X 1/2 in H, x1/2" H, Aluminum All season protection against drafts, moisture, dust and insects Heavy duty aluminum for long lasting seal and durability Meets code for wheelchair access Seals gaps up to 1/2 inch high 4 inches wide by 1/2-inch high by 36 inches long