The Seasonic SS-300TFX power supply is rated for a combined, continuous output power of up to 300 watts.  Unfortunately there is no mention of the rated operating temperature either on the PSU label or in the specifications.  The SS-300TFX features a single +12V output, Active PFC and universal AC input.

Specifications for the SS-300TFX:

Cables

The Seasonic SS-300TFX PSU comes with a basic set of hardwired cables.

(1) ATX 24-pin

(1) ATX 12V 4-pin

(4) SATA

(2) 4-pin Molex

(1) 4-pin FDD