We use a first-principle quantum-statistical method to derive the expression of the entropy production rate in relativistic spin hydrodynamics. We show that the entropy current is not uniquely defined and can be changed by means of entropy-gauge transformations. similarly as the stress-energy tensor and the spin tensor can be changed with pseudo-gauge transformations. We show that the... https://www.footballmediaservices.com/product-category/carbon-steel-tig-rod/