Tetra EasyCrystal Filter Pack C250/300 filter material with activated carbon, filter pads for EasyCrystal internal filters, suitable for aquariums from 15-60 liters, 3 pieces, Green : Amazon.co.uk: Pet Supplies
TETRA IN 300 AQUARIUM INTERIOR FILTER OVER 10 TO 40 LITERS 4004218174870 | eBay