I just noticed that on an ePMP 4600 that I was going to deploy soon that the SFP port hole is too large for the threaded fitting or the fitting is too small. The ethernet port one works but neither of the two that came with the AP will fit on the SFP port.
The two on the left came with the 4600 and the one on the right came with the 4500. The 4500 one will work on the SFP port of the 4600.
The one that will work is M25x1.5 and the one that will not work and came with the 4600 is M28x1.5.