Right-to-left Support
The RadSlider fully supports right-to-left (RTL) language locales. In order to turn on the RTL support you should set its IsDirectionReversed property to true as well as dir=rtl to the html or body elements or to its direct parent.
<div dir="rtl">
<telerik:RadSlider RenderMode="Lightweight" runat="server" Skin="Simple" ID="RadSlider1" Orientation="Horizontal" Width="300"
Height="50" MinimumValue="0" MaximumValue="50" LargeChange="10" ItemType="Tick" IsDirectionReversed="true"
EnableServerSideRendering="true">
</telerik:RadSlider>
</div>
