Replacement packing head o-ring part (I 605 1) for Eclipse HP-BCS, HP-SBS, HP-CS and HP-BS airbrushes. Also fits Hi-Line HP-AH, HP-BH, and HP-CH airbrushes. Also fits High Performance HP-AP, HP-BP, HP-SBP, HP-CP, HPBC1 plus, and HP-BC2 plus airbrushes.