This is a Scott # 145-155, Set of 11, Used; the 154 has a couple short perfs, top; otherwise, a nice group. Common terms/abbreviations: mint=never cancelled; OG=original gum; condition of OG: NH (never hinged), LH (light hinge mark), HR (hinge remnant), HH (multiple or unusually large hinge remnants); sound=no thins, tears, creases, stains, perf damage or alteration, significant fading, heavy pen or pencil marks on back, or other major faults (this excludes straight edges, poor centering, heavy cancels, or other problems clearly visible in the listing photo). Extensions of the return privilege are available, upon request, for those wishing to obtain PSE, PF, or APEX certifications.