... Easy installation, 100%satisfaction guarantee, Environmental protection material. continuous ink supply system for Epson workforce Pro WP-4531 ... pp material adopt advance technology for use longer timeCISS/Continuous ink supply system ----The refillable ink tanks will ... empty), compatible ink cartridge, remanufactured ink cartridge; 2). continuous ink supply system/CISS: ordinary CISS, "D" model CISS ...