The spring is bare steel. Fits International Models: I4, I6, ID6, H, H, HV, HV, Super H, Super H, Super HV, M, M, MD, MD, Super M, MDV, Super MTA, Super MTA, MV, Super MVTA, Super MVTA, O4, O4, O6, O6, ODS6, ODS6, OS4, OS4, OS6, OS6, Super W4, W4, W4, Super W6, W6, W6, Super WD6, WD6, WD6, 300, 350, 400, W400, 424, 450, W450, 2424.
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