Ametek Crystal T Series [T-1-CPF-FOV] Hydraulic Comparator Pump F System (Oil Version) 0 to 15 000 psi. Type T hydraulic comparator (System F) is a self-contained high volume pressure source capable of producing pressure up to 15 000 psi. It is ideal for testing gauges and setting hydraulic relief valves and pressure switches. Multiple models are available for hydraulic oil, water, or both.