Webb A25 (old# A24a), 10c Blue Plane over Globe Air Letter Sheet (Aerogramme), unused, watermarked, Cat. $375
when unfolded the watermarks are visible at the upper left and upper right hand corners of the sheet (see scans)
very slight wrinkling on UR corner and right flap.
small number 53 on RH gummed side of upper flap, likely a PO counting number (workers would often number their stock sequentially so as to keep track of quantities on hand and not have to count them all the time)
dotted address lines differentiate this from A20 thru A23
