Product Information Made in France. These Universal Filter Socks from Aquarium Systems will fit in almost any sump.They are 25cm in length, and measure at 10cm in diameter. You can pick the right thickness for your system, and collect finer particles if you require.These unique filter socks differ by having a fully cylindrical bottom, and do not taper like other filter socks. Measurement: Length: 25 cm Diameter: 10 cm Microns: 50um