Selenoids for a matrix config.....

I would like to get some help from you guy in a situation that I have found myself in.
I am looking for some small solenoids, either air or electronic ones,
that can create around 3 or 4 pound pressure and can hold it for a couple of minutes. They would be setup in a matrix way and driven by a PC. I am clear on the way I like to use them, only I am not sure what is out there, and most of all, how cheaply is it possible to get!?
If the test would work and I can create the whole project that I am planning to use them for, I would need over 100 pieces of them!
They need to be only single directional one, so spring retraction is OK! In diameter, should not be more than 40 mm, yet the rod should be up to 150mm.
If I am too vague, is because I am only researching for now on the technology that I can use. Once I get some feedback, I should be able to be more specific in details and in needs
Thanking to who ever gets back to me.
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