SR SUN RISE ARY002 Shower Arm Square 7.9 Inch 200mm Ceiling Mounted Arm of Solid Brass Chrome Finish The longer thread is standard NPT 1/2" connection Length: 200mm (7.9 inch) Only suitable for Ceiling Mount installation Chrome plating doesn't oxidize or corrode Easy & fast installation, no tool required.5 year warranty Longer thread for ceiling mount. Shorter thread for rain shower head. Need to be installed with teflon tape.