The Marina Stainless Steel Thermometer is accurate and easy to read, It has a safety zone indicator for most tropical fish, Protect your fish from unsafe temperatures by keeping track of your aquariums temperature with the Marina Stainless Steel Thermometer, It is reccomended for use in freshwater aquariums, The Marina Stainless Steel Thermometer Features and Benefits:, - For fresh and salt water, - Accurate and easy to read, - Safety zone indicator for most tropical fish, - Protects fish from unsafe temperatures, 4, 5"" length SKU: RCHG0057