英國STAR伺服閥的饋線桿是由比一般鉆石更堅固的藍寶石制作，使用中不會磨損或破裂，從而預防了無效變速和漂移，其終端口也有藍寶石制作，防止閥的進口磨損和污染，從而大大延長了閥的使用壽命，提升了閥的穩定性和可靠性。STAR閥、STAR伺服閥、STAR液壓閥
STAR伺服閥主要用在電氣液壓伺服系統中作為執行元件(見液壓伺服系統)。在伺服系統中，液壓執行機構同電氣中，液壓執行機構同電氣及氣動執行機構相比，具有快速性好、單位重量輸出功率大、傳動平穩，抗干擾能力強等特點。

STAR Hydraulics has released a new range of electro-hydraulic servo valves, including miniature units to suit underwater robots. They are available from Hylec Controls .
The industrial servo valves with integral electronics offer monitoring of spool position and improved static and dynamic characteristics. These features make them suited to industrial applications such as screw down systems.
Another recent addition is the new range of high-flow, mechanical feedback servo valves. They feature a high power pilot stage, providing performance previously available only with smaller flow valves. These two stage valves offer lower noise and threshold than conventional three stage servo valves. This makes them ideal for fatigue test rigs.