IP Ratings are a system designed to classify the degrees of protection or sealing that your electrical component has from foreign objects, such as fingers, tools, dust, and moisture. This system is recognized in most European Countries and is outlined in BS EN 60529. This classification system uses the letters IP, abbreviated for "Ingress Protection", followed by two digits.
The first digit represents the protection your component has against solid objects, including protection from hands, tools, wires, dust, etc. The larger the number, the greater the components protection from solid objects. The second number represents the components protection from liquids. The lower numbers reflect moisture from humidity, increasing to sprays of water, jets of water, to total immersion. For example, an encoder that is protected to IP65, is dust tight (dust will not enter) and is protected against low pressure jets of water in all directions, with limited ingress. The larger the IP number, the greater the protection.
Many of Encoder Products Company Units Like the Model 725 can be sealed to IP66. This means EPC encoder is protected from dust, and strong jets of water in all directions with limited ingress.