How to add a fast new SSD to your old Mac or MacBook for only $150 - 9to5Mac
How To Replace Your MacBook Air SSD
Amazon.com: 256GB SSD Hard Drive for Apple MacBook Pro Air 11" 13" 15" A1502 A1398 A1465 A1466 (Late 2013-2015) / OSX Sierra/Mac Pro A1481 : Electronics