From the Library List Supplement Published by Sawyer's - December, 1955
REELS OF SPECIAL LOCAL INTEREST
From Harry zur Kleinsmiede's book View-Master reels and Packets - A Collector's Guide Value 2 - U.S.A. and Canada - P. 332
The View-Master SP-Reels were intended to be sold in the vicinity of tourist attractions, as such, they were not distributed nationally, though they could be obtained from Sawyer's via Mail Order or ordered from a View-Master dealer.
SP reels numbered lower than 9000 usually were identical in content to the same reel without the SP prefix, for instance reel 67 and reel SP-67 have the identical images.
Some SP-reels numbered higher than 9001 were re-issues of lower numbered reels, for instance, SP-9009 was formerly reel 5.
Some SP-reels numbered higher than 9001 were reissued in identical versions or as new editions with the SP prefix, for instance reels SP-9002 and 9002.