Single best shoulder pre/rehab exercise

[SoupNaziNazi]

If you could only pick one exercise to perform for shoulder prehab/rehab which would it be and why? I'm a fan or the Cuban press personally

 

[Bearmode]

Face pulls

 

[lifted67]

Love these: Invalid Link Removed

 

[PaulBlack]

Lying L-flyes (you only need about 5-10 pounds to work the cuff muscles).
Maybe the shoulder horn.

 

[Studhorse]

External and Internal shoulder extensions with bands or cable

 

[RegisterJr]

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[Gutterpump]

PNF - D1 / D2 movements (as prescribed by my PT - I went through PT post surgery)