Molded tantalum at 50 V — the bulk decoupling choice
The 800 mOhm ESR is the number that matters for ripple current and self-heating — in a 50 V rail, the ripple current capability is limited by the ESR, not the capacitance. The 2917 case (7343 metric) is the standard footprint for this density; the molded construction gives a sealed body that resists moisture ingress better than a dipped part.
Temperature span and where it fits
The 125°C ceiling is the case temperature, not the ambient — derate the voltage above 85°C per the manufacturer's curve.