Push/Pull Solenoid Biasing

Hello. When a solenoid is labelled as just push or just pull, does that mean that an external bias force is required like a spring to "reset" the solenoid? And a push/pull solenoid does so depending on the polarity of the input voltage?

Thanks

it has been my experience a single direction solenoid will be labeled "spring return" or "no return"

I have a few of both ... the magnet only pulls or pushs on the bolt, it is up to the spring to draw the bolt back to the correct position when power is removed. for the no return type, the bolt just falls out of the solenoid by gravity when power is removed.

two of mine are heavy duty door lock type, fail secure... the magnet retracts the bolt from its locking hole, drawing the bolt up into the body of the magnet. when power is removed, the bolt slides down through the guide assembly and into the locking hole. clearly they're designed for specific purpose and orientation.