PCIe SSD – Apple MacBook Pro 13″ / 15″ Retina (Late 2013, Mid 2014)
Amazon.com: OWC 1.0TB Aura Pro X2 SSD Compatible with MacBook Air (Mid 2013-2017), and MacBook Pro (Retina, Late 2013 - Mid 2015), and Mac Mini (Late 2014) : Electronics
Upgrading 2013/2014 Macbook Pro SSD to M.2 NVMe | MacRumors Forums