Ribbonrail HO Scale Track Alignment Gauges are make it easy to layout smooth, consistent curves or absolutely straight lines when using flex track. Simply slide between rails to correctly position rails. Helps in laying, spiking and joining rail. Track Alignment Gauges are precision machined to NMRA standards and will work on any code of HO Scale rail. Available in many curve radii as well as straight. See the entire line of Ribbonrail HO Scale track alignment gauges.