The Halo and Apollo Light Modifiers are built on umbrella frames and require no adapter rings. Easy opening and closing means quick set up and tear down. The square or rectangular shape of the Apollo allows you to scrim or control the light more readily, and allows for 104 degrees of light spread. The round or oval shape of the Halo allows for 140 degrees of wraparound lighting with a circular catchlight. The Halo Mono allows you access to the controls on the back of your monolight