Start with your main need: do you want a compact external drive for laptop use, or a solution to expand storage by replacing an optical bay in a laptop? For portable disc burning, a slim, USB-connected unit is ideal and in this range you’ll find drives described as OS Independent and portable, with USB 2.0 interfaces and a compact 9 mm profile. They commonly write at up to 24x CD and 8x DVD±R, with some bundles including burning software. For storage expansion, look at 9.5 mm thick HDD caddies that fit in laptops’ optical bays and come with bezels, mounting screws, and even dual-boot capability features. Choose based on your primary need and your device’s physical space.