These photos show the small pin hole variant beside the more common 740. It is speculation that these small pin hole 740's were made for an iron pin, rather than the standard wood pin. Very few of these have been found. This repaired example was located on an old railway right-of-way in Eastern Ont. There is word that a portion of one was removed from a building in Montreal Que. years ago. This insulator has quite an underpour on the base. The small pin hole measures just under 5/8" in diameter, versus the standard threadless diameter of 15/16". Insulators.com is a great place to share information and pictures!! Good collecting ......... Robin