A coupler system which changes the relationship of two or more rotating shade tubes is disclosed. The invention enables the installer to compensate for the height of the hembar by rotating the tube forward or backward any desired number of degrees. The coupler includes a cam which is adjusted by opposing set screws. The cam may be rotated by about 15 degrees in each direction. Adjusting the cam adjusts the second tube without adjusting the first tube (e.g., the drive or motor end tube). The adjustment device is configured to rotate the cam which, in turn, rotates the second tube to align a second hem bar hanging from the second tube with a first hem bar hanging from the first tube. The adjustments may be accomplished with minimal or no removal or adjustment of the other shades, and with minimal friction on the aligned shade.