Qty 1 = one packet of 10 water purification tablets. Each tablet = 167mg of sodium dichloroisocyanurate (aka troclosene sodium, troclosenum natricum, NaDCC, or SDIC) to treat 20-25 liters of water
This is the exact item included with the Water Rower rowing machine to keep the water clean. Drop one tablet in the tank every 6 months; one 10 pack = 5 year supply. Expires 4/2027 or later (file photo, brand varies)