1941 California Clipper cover from Sidney Australia to Commonwealth Felt Company, 74 Summers (sic) Street, Boston. No content. Two 2 shilling Kangaroo stamps is sufficient postage. Censor tape at left and tied to envelope with violet censor marking. California Clipper handstamp at lower right. Crease down middle of cover. No backflap. Clipper aircraft carried the trans-Pacific mail until they were halted after the attack on Pearl Harbor.