Features:
Twice as original sliding distance, conceptionally retractable.
8pcs Ball-bearings design, multiple adjusting way of sliding tightness.
Sliding Stopper built-in.
Super smooth transporting belt and track design.
1/4" and 3/8" threads built-in the bottom for connecting with tripod.
1/4" and 3/8" screws built-in the top for connecting with ball-head.
Built-in Spirit Level.
High precision CNC technics.

Specifications:
Brand: Commlite 
Model: CS-V500
Length: 50cm / 19.7in
Height: 6cm / 2.4in
Sliding Distance: 1M / 39.4in
Loading: 8Kg / 17.6Lbs
Item Weigt 2.24Kg / 4.9Lbs
Package Size: 55 * 13 * 9cm / 21.7 * 5.1 * 3.5in
Package Weight: 2.415Kg / 5.3Lbs