Finding the Flavor of Chocolate. Gregory Ziegler puts a small block of chocolate into a styrofoam bowl and sticks it into the microwave. Soon, a lovely sweet aroma spreads through the air, lending warmth to the otherwise bleak lab. Ziegler takes the bowl out of the microwave; it's filled with a thick, swirling liquid.
First Class Large Envelope/Flat Mail. Minimum size: 6 1/8 inches tall or 11 1/2 inches long and 0.007 inches thick. Maximum size: 12 inches tall x 15 inches long and 3/4 inches thick. Maximum weight: Up to 13 oz.
Size 16 envelopes qualify as flats as do the catalog envelope sizes 1Â¾, 3, 6, 8, 9Â¾, 10Â½, 12Â½, 13Â½, 14Â½, 15, 15Â½. The flats postage rate would cover international envelope size C4 but not C3. All items that are not letters, postcards or flats are considered parcels by the USPS.