It should say on the fence attachment that came with the bands - usually it is used as a post-throwing modality but it can work just as well as a shoulder warm-up if you lower the volume/reps a little bit. From my experience using those bands and exercises in college, it leaves the shoulder pretty fatigued immediately afterwards.
I prefer J-bands pre-throwing because its less resistance - just enough to get good blood flow without much fatigue. Crossover is more resistance and potentially better for building strength, but more fatigue, which is why its better post-throwing or as part of a shoulder prehab protocol in a lifting program.
Keep in mind its nothing magical just a series of exercises that target the shoulder musculature at a variety of angles (low, mid traps, rhomboids, rotator cuff - infraspinatus, supraspinatus, teres minor, subscapularis - pec major, minor, serratus anterior, front mid and rear delts).
For those of you reading this post wondering what a good alternative to Crossover Symmetry is:
high, mid, low reverse flyes x10 each (low, mid traps, rhomboids, post delts)
high, mid, low forward flies x10 each (pec major, minor, front delts)
side lying DB external rotation OR band/cable external rotation x10 (rotator cuff)
scap pushups x10 OR serratus wall slides x10 (serratus anterior)
dumbbell OR band frontal and lateral raises x10 (anterior and mid delts)