Toner Refill Store's premium compatible Samsung black toner cartridges contain brand new parts and are 100% guaranteed to meet or exceed your expectations and surpass the print quality of the OEM (Original Equipment Manufacturer) Samsung SCX-4521FG. Our Samsung SCX-4521FG monochrome toner cartridges are made from the highest quality materials and are manufactured in an ISO-9001 certified factory. Go green with our toner refill kits which allow you to refill your cartridge and reuse it! Our Samsung SCX-4521FG high yield laser toner cartridge have a 'One Year 100% Satisfaction Guarantee'. The use of our premium compatible laser toner cartridges for the Samsung SCX-4521FG does not void your printer's warranty.