I try to not bother this forum by calling out a lot of bad listings. And I presume that many folks know that US #315 is often faked by trimming off the perfs, it needs to be 21.5x25 mm or larger to get a cert.
But an
ebay seller named chesawc has a trend of offering trimmed #315s. Here is one of his current listings with a trimmed stamp (which has bids)
http://www.ebay.com/itm/US-USED-190...AOSw5dNWtlYvhttp://www.stampsmarter.com/screen/12168.jpghttp://www.stampsmarter.com/screen/17424.jpgTo his credit, he has added a note at the bottom of the current listing saying it might be trimmed. The perfs are visible as shown below.

The #315 is one of the most often seen trimmed stamps in the marketplace. If you are seeking a #315 their are two options to get a real one. Buy one with an exiting cert or take a chance on buying one that measures 21.5 x 25 mm or larger.
Don