RS Shapes Said:
"I am having the same issue. The only cases that I can find that fit the 2251 model all have ventilation slits on the bottom, and cover the actual air intake on the sides.[...]"
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Amazon Search Queue: A2251 case
Just use a Laptop Cooler:
Don't Use a Ventilation System Cover. With a venation system (fans for cooling it down), the encased MacBook Pro would be quite a bit bulky, heavy, and highly-prone to physical damage. If the plastic on the case were to snap, the MacBook Pro would predictably get a ding in it somewhere, as a result from the snap taking place.
Use of my Case and MacBook Pro:
So, I use what I mentioned above for the case, and, when using the MacBook Pro (as I am right now), I remove it from the case, and then place the MacBook Pro atop a laptop cooler. The Laptop Cooler plugs into the MacBook Pro. When use is complete, having used a Laptop Cooler, the MacBook Pro is cool enough to not overheat when placed back and zipped shut. I place each in standalone: The Zipper-Shut MacBook Pro and the Laptop Cooler in their own sleeve in my backpack.
OtterBox:
If you need to use such a case, OtterBox might have some ideas - I do not think they sell these items for MacBook Pro. Go here and perform a Chat Session (Click: The Annotation Emblem on the Bottom-Right Corner): https://www.otterbox.com