Linear Guides MGN Series: 400mm MGN9 linear rail guide with MGN9H blockThere are 20 holes on the rail for fixing the rail to the machine with nut and screwThere are 2 Transparent rubber stoppers on the ends of the rail in case the carriage falls off the rail, please remove them after assembling the rail on your machine if necessary.Style:MGN9Hsize:400mmMaterial:metalcolour:Silver+GreenPackage Contents:2 x MGN9 linear rail guide 400mm length2 x MGN9H carriage block(been installed on the rail)4 x Transparent rubber stoppersOnly the above package content, other products are not included.Note:Light and different displays may cause the color of the item in the picture a little different from the real thing.The measurement allowed error is +/- 1-3cm.