The bottom rail includes compatible dovetail that works with Arca Type clamps while the slider is equipped with quick release clamp. The clamp can be oriented in 4 positions using the center screw and dowel pins. Camera to subject distance can be adjusted in fine increments using High-precision 100 TPI (100 turns per inch) Screw with 0-50mm range. Screws are a cost-effective alternative to micrometers where position readout is not required. Rail will work in 90 degree orientation (perpendicular to the ground) with load up to 10 lbs. When rail is in horizontal orientation (parallel to the ground) it can hold up to 15 lbs.