A 

 is a form of quarter-turn 

 which uses a hollow, perforated and pivoting ball to control flow through it. 

 are durable, performing well after many cycles, and reliable, dosing securely even after long periods of disuse. These qualities make them an excellent choice for shut off and control applications, where they are often preferred to 

 and 

. The 

 are applicable for air. gaseous, and liquid applications requiring bubble-tight service, Low-point drains and high-point vents in liquid, gaseous, and other fluid services, Instrument root 

, Cooling water and feed water system, Steam service.

A 

 is a form of quarter-turn 

 which uses a hollow, perforated and pivoting ball to control flow through it. 

 are durable, performing well after many cycles, and reliable, dosing securely even after long periods of disuse. These qualities make them an excellent choice for shut off and control applications, where they are often preferred to 

 and 

. The 

 are applicable for air. gaseous, and liquid applications requiring bubble-tight service, Low-point drains and high-point vents in liquid, gaseous, and other fluid services, Instrument root 

, Cooling water and feed water system, Steam service.