The M1 filters I just picked up from Farm & Fleet are different than the older ones I had in my stash. The spring at the top of the filter is gone, when you look into the hole it is now a blue plastic button of some sort (on the M1-103). The M1-102's have no spring at the top at all, but there is one at the bottom now (bottom being near the threads).
Don't know what this means but I thought it was interesting.
Don't know what this means but I thought it was interesting.