Couple of things for you from my past experiences.
First: mesh breeder boxes don't work for shrimp...they suck. They will work in a pinch and certainly long enough for you to get solid ones but take my advice on this. Reason being, the shrimp actually can climb the mesh out of the breeder box and either get back into the tank or worse (as I have had done) go over the other side and onto the floor. The worse thing of all is that it provides no protection for selective breeding since outside shrimp can breed through the net if conditions are perfect (I have witnessed this myself).
I have used breeder boxes extensively for years in order to selectively breed my shrimp (and fish before that). I have found there is only one that I like...the Marina Breeder box. It comes in two sizes, and I prefer the larger. It is an external box with an internal air lift tube which draw water from the tank into the box and then overflows out. They are AWE SOME!
The only disadvantage I have found is that it prevents your tank lid from closing which cause evap and temp loss as well as exposing your tank to outside threats (ie dragon fly larva etc) through the now open tank top.
ALSO, very important for keeping shrimp in these specific breeder boxes...you MUST cut a piece of sponge in a square shape to perfect fit the overflow of the breeder box to ensure that the shrimp do not exit the box. The little "grate" they give you is not adequate for smaller shrimp.