660me15 = 6.60 me 1.5 for PSP 1000 and PSP 2000 (non TA88v3+)
660lme15 = 6.60 lite me 1.5 for PSP 3000, PSP Go, PSP 2000 w/ TA88v3+

Both files are included with this download, make sure to use the correct one with your PSP, do not install both.
