Extend the height between the equatorial mount and the tripod to prevent collision with the tripod or other parts that affect the adjustment when adjusting the elevation angle 150MM fixed extension rod + 100MM long rod + 50MM extension rod, the length can be increased or decreased according to your needs. Used to increase the height between the equatorial mount and the tripod to avoid collision or failure to rotate due to adjustment during use. Colour:Black & Silver Material:Aluminum alloy Package Contents: 1 * telescope Extension Tube kit Only the above package content, other products are not included. Note: Light reflection 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.