Do I need to buy quick release spring bars if I already bought a quick-release strap?

No — our quick-release straps come with spring bars included. These additional spring bars are handy if you need replacements, want odd-size spring bars for a non-standard watch, or want to add quick-release functionality to a strap that didn't come with them. They are also handy to use with military style straps if you want an easy way to switch between those and quick release straps.