Small solenoid

I'm thinking on using a small solenoid to control a box opening.
I've seen an example in this video.

The soloneid of the video is a pull-push one:

I guess that one end is the pull actuator and the other end the push actuator.

I've found on ebay a few cheap 5v solenoids, which I think is great because I wont need a relay, just a transistor to control it but I'm not very sure on what to get. I think what I need is a pull solenoid (like this one, I imagine) but for the same price there is this pull-push one which I could use for other experiments.

From the photo I don't get how this is pull-push as only seems to have one end?
Does anybody know how this works?


If you look at that Ebay page and scroll down a little, you see the solenoid from the other end, and there is the core sticking out.

All those solenoids are almost the same. The spring keeps the core to one side, and when powered the cores moves in the other direction compressing the spring.

Thanks a lot!

Look out for the maximum on-time and duty-cycle - most solenoids will melt down
if powered continuously.

I just want to open the box, that's 1-2 secs max