The red covers sit above the plane of the mounting lugs so the wires would normally go out the ends but they could also go out the sides if they weren't ganged together.
The thing I didn't like was the covers are rubber and there are solid wedge shaped plastic pieces from the base the push up through the cover and hold it in place. The covers just don't snap on and off easily and the molded rubber isn't perfect in this area. I'm very picky about such things, but others might say its fine.
I used the Littlefuse fuse holder instead.
These are similar. They actually are not quite as rugged as the ones I have up for sale, but the covers are plastic like the base and they too can be ganged. You have to make your own bus bars and if you want to bus them you have to cut the covers to allow the bus bar to exit the cover.
I'm going to give everyone one last chance on these before I toss them.