BOB, No, do not file it! If you just have the white plastic piece that does not fit, you have the part that is made for the Master IV and V, The proper I'cone for your meter has TWO pieces, the cone and a piece called the auxiliary multiplier used in normal lighting to partially mask the cell and to switch the meter to high scale. I have the manual for the Invercone for the Master I, II and III, but I have no facility to copy it other than the local Kinko's Copy Shop. I cannot scan and send it to you except by mail. Jerry Rea1eye@xxxxxxx wrote: > I just purchased a Weston Master II meter and it came with a > plasticinvercone. Could someone explain how to get it to fit ( I > think it needsto be filed down). Can it be used on both scales ( > 25-1600 and0.2-50 )? My understanding is that it is used when you > want touse the meter as an incident light meter, so you would point > themeter at the camera ). Thanks,Bob ( Meter is Sangamo Weston, > model S141/ 735), made in England. )