This tool is made of POM, used to align the HGR15 or MGN15 linear rail on a 20 profile extrusions.
By using this tool, you can ensure the linear rail is straight. This is important when using two rails with one plate such as an X-Axis or Z-Axis. If the rails are not aligned correctly the movement is affected.
But using the alignment tool when installing linear rail on to 20 profile V-Slot you can ensure the linear rail is correctly mounted.