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 & Weight Requirements. 1  Postcards Postcards must be rectangular to qualify for First-Class MailÂ® prices. 2  Envelopes Standard Sized Envelopes Envelopes must be rectangular to qualify for letter prices. 3  Large Envelopes Large envelopes must be rectangular to qualify for flat pricing. Large envelopes that exceed size requirements of a letter will be charged package prices. Packages Packages can be sent using Priority Mail ExpressÂ®, Priority MailÂ®, First-Class MailÂ® Parcels, USPS Retail Groundâ¢, and Package Services. Contents must not weigh more than 70 lbs. Lower weight limits may apply. Girth is the distance around the thickest part of the package. In most cases, the maximum combined length and girth is 108 inches.