Package Listing: 1 x Seat post mount, 1 x 28.6mm Spacers, 1 x 25.4mm Spacers,1 x M2.5 Hex Key Wrench. If you have any questions, please feel free to contact us. Sturdy Material & Design -- Created from advanced injection moulded co-polymer. It is strong enough to keep your electronics where you want them on your bicycle no matter how bumpy the terrain. Compact & Convenient -- This seat post quarter turn mount perfectly position your Varia radar or tail light on your bike so you can focus on cycling. Simple & Strong -- Very simple and strong handlebar mount compatible with Variant Rearview Radar, Variant Smart Bike Lights. Tool-free installation. Compatible -- compatible with Garmin Varia RTL510 / RTL515 / RVR315 Rearview Bike Radar. Widely used in most road bikes bars for 25.4mm, 28.6mm, 31.4mm.