A bare shaft actuator is normally used with operational media air, gas, hydraulic oil or water. A wormgear actuator is normally used for electrical operation.

Pneumatic, bare shaft (linear) actuators are usually selected for smaller valves, larger number of valves in plants, faster openings and shutdowns, and repeated larger numbers of operation per time cycle, but also used for larger valves.

Electric operated valves have had a number of improvements the last 30 years, and are now more than previously covering areas dominated earlier by pneumatic valves, especially because of the integrated control possibility. (But not only)

Wormgear actuators, with the correct electrical actuators, can operate more precise, be stopped in midway positions, open slow and continue faster, but also be of simpler (and cheaper) construction for fairly fast opening and closing. Suitable for valves from (say) 150mm and up to largest and up to highest pressure classes.

With modern electrical actuators complete 'internet of things' units can be supplied as an integrated part of the actuator saving a lot on cabling and external control units.

Actuators should be selected on principle best price over lifetime, including maintenance and operation cost. Detailed valve application and construction, operation cycles per time unit and operation time without required maintenance, max/min acceptable closing and opening time (money saved on electrical actuator if geared down) etc.etc.