Feasible 3D Printed Snap Connectors
If the equipment has to be removable, then there's no point in trying to make a one-piece object in the first place.  So it looks like you have two problems. The first is to decide what's the best way to split your container to facilitate both putting the equipment inside &amp; removing it; the second is how to latch the two together.  I can't answer the first since you haven't shown us the equipment.

As to the second: there are a number of plans for spring-latching connectors (such as used with straps, backpack covers, etc) on thingiverse.com.  If you have no constraints on the exterior of your container, I would just merge the latching connectors into the container wall (e.g. with meshmixer) .