Face Pulls are an awesome exercise that work the rear delts, traps, and upper back. It's a compound movement that allows for fairly heavy weights to be lifted for these relatively small muscle groups.
I recommend doing face pulls with either a back workout, to work the upper back. Or with a shoulder workout to target the rear deltoids. You can even do them with a chest workout to help balance out your shoulders with some extra rear delt work. This will help compensate for all the work the front delts get when doing chest training.
Most people like to do face pulls with a rope attachment. But one draw back with using the rope is that it can be a bit awkward on the wrists and you may find that you lose your grip when lifting heavy weights.
But a good alternative to doing face pulls with a rope is using 2 single handle attachments instead. Most gyms these days have nylon handles and they work great for doing face pulls. Simply attach 2 handles to the pulley cable and perform the facepull as you would with a rope attachment.
The benefit of using 2 handles is that you'll be able to have a more secure grip and keep your wrists in better alignment.
I suggest you try doing both variations and see which one feel most comfortable to you and which one gives you the best workout in the rear delts and upper back.
Lee Hayward brings face pull moves for you in this one. These are great movements which will work on the rear delts, traps, and upper back. It is a compound move and you can do it with your regular back exercise. These workouts will tone up your shoulder muscles and also enhance grip strength. Watch this video, match your steps with Lee and have stronger, larger muscle group.