<https://racersedge.co.nz/product/blackburn-multi-mirror/#product>
<http://schema.org/description>
"A lightweight and adjustable mirror that fits snugly into the end of your bar when you need to have a quick glance behind without fitting something that impairs your movement. \n\nUnlike other handlebar-mounted mirrors, the Multi-Mirror fits inside your handlebar, so there's nothing under your hand. Simply pull out the bar end plug of your handle bar and insert the Multi-Mirror with the correct shim to make a semi-snug fit, then twist the expansion nut until it feels solid. Your handlebars need to have an inner diameter of at least 20 mm in order for the Multi-Mirror to fit.\n\nFeatures:\n\n\t\n\t\tUniversal fit plugs into virtually any bike/handlebar configuration\n\t\n\t\tLarge mirror for extensive field of view\n\t\n\t\tEasy installation and adjustments\n\t\n\t\tFits inside your bar—nothing under your hands and theft-resistant"
<https://racersedge.co.nz/product/blackburn-multi-mirror/>