Ooops, I screwed up for the first time ever!!!!!!!!!!!!
The INSIDE dimensions are 1' and 1-1/4" respectfully! Ed these are double type grommets that normally go through a firwall type assembly-where as one 'flange' of the gommet will fit on one side of the wall and ther other edge is forced through to the hole to the back side, holding the entire grommett in place.
DV