Something I never understood about some online shops, the drop-down with only one option, usually "standard". What is "standard" doing there? What does this fie

Something I never understood about some online shops, the drop-down with only one option, usually "standard". What is "standard" doing there? What does this field mean? Example: http://alexstore.shoply.com/product/lava-lamp/ http://alexstore.shoply.com/product/lava-lamp/