Bootstrap generate fixed width col, but just for large displays, for smaller displays responsive

I would like to generate a fixed width col for big displays with bootstrap, but it should be reponsive if you use it on smaller ones.

<div class="container">
<div class="col-md-3"></div> <-- this should be fixed width 400px for big displays
<div class="col-md-9"></div> <-- content should be always responsive
</div>

Is this possible? Thanks