Hello,
I recently ordered 2 of item 39-317, and 2 of 39-318 along with other parts. The 39-317, 39-318 were not the exact copy of the window part at my home. The holes do not match up and the arm on the new piece seems to be shorter.The window information is NFRC 100/200, series: twvca, code: PAT(VA), MST 2040.
The device on the left is the one I am trying to replace. The one on the right is the ordered that did not match
I wouldn't worry about the holes in the sill plate. Ours are specifically made with more holes than you'll ever need to cover multiple previous configurations.
The fact that it extends further is a little worrying, though. Would it be possible to see it flipped around from the other side?
I took one of our 39-315 operators out of stock to take some dimensions. I measured both arms like you show in the photo and it comes out at 7-1/2" and the Link arm is 5". As for the installation hole locations you will need to make new holes in your window sill. I don't think the size of the base matters other than that detail. Yours must be an older version of our more modern part. Also important to note that the 39-315 does not come with the Detach clip 39-105, which is sold separately. Otherwise I do think this is your best bet.
