Perhaps you bought air/pro with low capacity SSD to save money,but you don't need to spend much more money for original high capacity SSD for it,then you can choose this adapter card because nVME SSD is cheap and fast now.
This adapter is compatible with the following air/pro Models
(Note: requires macOS 10.13 High Sierra or later)
Pro:
2013 Pro Retina A1398 A1502 (ME864 ME865 ME866 ME293 ME294);
2014 Pro Retina A1502 A1398 (MGX72 MGX82 MGX92 MGXA2 MGXC2);
2015 Pro Retina A1398 (MF839 MF840 MF841 MJLU2 MJLT2 MJLQ2);
Air:
2013- 2014 Air A1465 A1466 (MD711 MD712 MD760 MD761);
2015 Air A1465 A1466 (MJVM2 MJVP2 MJVE2 MJVG2 MMGF2 MMGG2);
2017 Air A1466 (MQD32 MQD42 MQD52)
and Pro ME252 MD878 for iMAC A1419 (Later than 2013 and newer).
Supported Following nVME SSD:
NVMe SSD : SX6000, SX7000, SX8200, SX8200 Pro etc
Corsair : MP500, MP510
Crucial : P1
HP: ex920, ex950
Intel NVMe SSD : 600p, 660p, 760p
Toshiba XG3-XG4-XG5-XG5p-XG6 line