Note: This RAM module only fits in Windows laptops. For a MacBook or iMac, this RAM isn't suitable. The laptop needs to have a DDR3 connector. You can check this in the Windows Task Manager by clicking 'More Details' under the 'Performance' header. It'll say DDR3 or DDR4 under memory. If it doesn't say anything about the connector, you'll need a DDR4.
The Crucial Standard 4GB SODIMM DDR3L 1x4GB is a 1600MHz module with 1.35V suitable for use in laptops. This module comes with a lifelong warranty from Crucial.