Hello,
I would strongly recommend getting the metal Mity Vac Silver line edition as the link suggests above at Harbor Freight. I have broken 2 plastic versions already and in my opinion I have not abused the pumps. One pump actually simply won't hold vacuum and it initially caused me to mis-diagnose stuff until I realized the vacuum pump was bad.

If you can aford the extra bucks, spend a little extra and get the metal one - you won't regret it.