What is mono grade?

Monograde refers to a type of lubricant, typically engine oil, that has a consistent viscosity at various temperatures. Unlike multigrade oils, which can perform well across a range of temperatures, monograde oils are designed for use at a specific temperature range. They are often used in older engines or in specific applications where consistent performance at a certain temperature is required. Common examples include SAE 30 or SAE 40 oils.