Caterpillar 9T0973 9T-0973 Hydraulic/Transmission Filter Advanced High Efficiency Advanced Efficiency Hydraulic Oil Filters protect your system against accelerated wear with special filter media engineered to provide greater protection in moderate to severe applications. Cat Hydraulic Filters provide the best protection from contaminates and abrasives by keeping them from wearing down the tight tolerances within the high pressure hydraulic system. Cleanliness is the key to maintaining proper lubrication of your sensitive hydraulic system. Efficiency Rating: Advanced Efficiency