RM1-1531-000CN -fuser assembly - Bonds the toner to the paper with heat - For 220VAC to 240VAC operation - For Laserjet 2400 1--RM1-1491-000CN -Fusing assembly - For 110VAC to 120VAC operation - Bonds the toner to the paper with heat; 2--RM1-1531-000CN -Fusing assembly - Bonds the toner to the paper with heat - For 220VAC to 240VAC operation - For Laserjet 2400