The 4.5 kA breaking capacity per EN 60898 covers most domestic and light commercial panel duties; the higher 6 kA per IEC 60947-2 gives you the rating for industrial distribution boards where the prospective fault current is higher. If you're specifying against UL 1077, it carries a 5 kA interrupting rating there too.
Mounting position is any, which helps when you're cramming a row of breakers in a shallow enclosure.
Halogen-free and silicon-free construction, so it's suitable for clean-room or sensitive electronics environments where outgassing matters. Sealable option is available (toggle lock) for applications requiring tamper-proof isolation.