1 No effect to your Macbook and easy installation.
2 Protect your laptop against dust and moisture.
3 Material: The case is plastic hard case (include top case and bottom case)
About Model Number:
Please kindly check the model of your Macbook before purchasing!
Note: If youre not sure the model, please kindly check the back of your macbook, you could see the model (Axxxx) printed there.

Compatible model details:
1.For 11" MacBook Air :
Model: A1465, A1370

2.For 12" MacBook :
Model: A1534

3.For 13" MacBook Pro :
Model: A1278

4.For 13" MacBook Pro with Retina display :
Model: A1502, A1425

5.For 13" MacBook Air :
Model: A1369, A1466

6.For 15" MacBook Pro :
Model: A1286

7.For 15" MacBook Pro with Retina display:
Model: A1398

8.For MacBook Pro (13-inch, 2016, Four Thunderbolt 3 Ports) /
For MacBook Pro (13-inch, 2016, Two Thunderbolt 3 Ports) :
Model: A1706, A1708

9.For MacBook Pro (15-inch, 2016) :
Model: A1707