[Compatible with for Whisper filter] The size of filter 5.1 in L x 6.7 in W. It is match perfect for large whisper bio-bag external filter PF20, PF30, PF40, PF60, for whisper external filter IQ20, IQ30, IQ45, IQ60, for whisper 20i and 40i internal filter. Good idea for Fauna ReptoFilter 50 gallons (125 GPH). [Superior Filtration Performance] Made of dense double-sided superior cotton and super activated carbon, it provides triple water filtration that removes 99 percent of filter debris and fish waste, keeping the water clean and healthy and promoting healthy fish growth. [Replace Filter Regularly] To optimal cleanliness, we recommend replacing the aquarium filter cartridges every 2 to 4 weeks for your fish tank.It contains 12 pack aquarium filter . Colour:As Shown Material:Composite Materials Package Contents: 12 x Large Filter Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is 1-3cm.