【Protect Shrimp and Fish】Multi-layer filtration of filter cotton completely prevents shrimp and fish from being inhaled. 【Prevent clogging】 It can prevent large foreign matter from being sucked into the filter system and clogging. 【Uses】Suitable for aquariums, protecting shrimps and small fish, and purifying water quality. 【High Quality】Our aquarium filter cotton is made of high quality sponge with good filtering effect [Increase the oxygen content of the aquarium] The principle of biological filtration uses multi-layer filtration to cultivate high-density nitrifying bacteria to achieve the effect of increasing the oxygen content of purified water Size: total height 15.5CM. Cotton height 6.3CM, cotton diameter 7.5 When starting to use, if your water goblin floats on the water, please squeeze it with your hands to make the biochemical cotton completely absorb water, and it can work normally. Friendly reminder: In order not to affect the normal filtering effect, it is recommended to