For what it's worth, I have an old Sony PC100 video camera and about 4 or 5 of the M series batteries...a couple of which are Sony Infolithiums. I definitely like using the Impact 7600mah L-series the best since it has the best run-time, but I've had no problem at all with these M-series batteries working with the 702. The post holes on the battery are nice and deep and seem to engage really nice with the 702 posts so that there's a snug fit, but not too snug. Since the M-series batteries are shorter than the L-series, you want that snug fit because the pin isn't there to keep the battery from sliding off the posts if there's not a snug fit. Anyway, I've had good luck with the M-series batteries...the main disadvantage is that since they're smaller they also have a smaller capacity.