Manfrotto 391RC2 3-way Head with Quick Release Plate

I use the 391RC2 head on both my tripod and Manfrotto Car Window Mount and am thrilled with how smoothly it pivots in all directions. For my field research I have to use a window-mounted scope hundreds of times a day to read color bands of shorebirds. This head can easily swivel and then be locked in place so you can have your hands free to take notes or adjust the focus, coming loose again with another twist of the handle. My only complaint is that you have to be very careful how you set your scope down again (or remove it from the head altogether using the quick release) because the scope can twist if it is jostled, which can strip the threads of scope attachment.