Does anyone know what the SR means in model number “AL-525GG4FBS26-SR”?

Jomashop has the same item wo the SR for $150 more and I can’t find a difference other than the straps but they are both leather so I can’t imagine that is causing the $150 price difference.

Jomashop has the same item wo the SR for $150 more and I can’t find a difference other than the straps but they are both leather so I can’t imagine that is causing the $150 price difference.