Koller Products TOM Aquarium Carbon Pillow 2 pack fits Rapids Pro Filter #1350, 1351, 1315 & #1316 Fits variety of Rapids Pro Filter models Premium activated carbon effectively removes discoloration and harmful chemicals Poly-fiber traps large particulate matter and other wastes Fits Rapids Pro Filter models: RP3 (TM1350), RP3 Plus (TM1351), PS3 (TM1315), and PS4 (TM1316) Includes two pillows