Suitable for study of linear motion under nearly frictionless conditions. The kit consists of square section aluminium track, length 1.5m, with two rows of fine holes along the top. Supported on two light alloy castings. One support has a two point contact and other a one point contact for lateral and orizontal adjustments by means of a knurled screw. One end of the section is fitted with a tube for connection to blower and the other end is closed.