This pair of VariTube 15mm Support Rods (5.9-9.1") from Chrosziel makes it easy to extend the length of your camera-support rig – without buying additional pieces. Add a long telephoto lens and extend the rods for proper support.
With a quarter-turn, the internal clamping of the telescopic rod releases and you can extend or retract the rod. These rods feature a variable length of 5.9-9.1". There's a "cap" at the end of the rod that measures 0.8" long; this part has a standard 15mm diameter for attaching a matte box or other accessory, or for attaching to a camera baseplate.
The extension is made of solid aluminum and fits snugly within the outer rod, which is also heavy-duty aluminum. The construction of the VariTube makes it easy to adjust with smooth sliding even while the rods are bearing a load.