HOB LED light

HOB has a LED light indicator that flashes when water can not pass thru the cartridge indicating time to change cartridge. Provides mechanical, chemical and biological filtration. Includes 3 boxes of replacement size M cartridges. 2 boxes have 3 cartridges each and 1 box has only 2 cartridges and 3 specialty ammonia remover size 10 pads. All for $60