The Siemens 3VA1150-5EF36-0CA0 is a SENTRON molded case circuit breaker (MCCB) rated for 50 A continuous at 40 °C, with a 3-pole configuration and a TM240 thermal-magnetic overcurrent release.
This MCCB carries a 187 kA interrupting rating at 240 VAC, dropping to 121 kA at 415 V, 75.6 kA at 440 V, and 17 kA at 500 V and 690 V. For a 480 V panel (common in North America), the 75.6 kA at 440 V is the closest published figure — expect a similar or slightly lower rating at 480 V. The 17 kA at 500 V and 690 V tells you this breaker is not intended for high-voltage distribution; it's a 240–480 V class device.
Current derating — don't size at the 40 °C number alone
At 55 °C it derates to 49 A, at 60 °C to 48 A, at 65 °C to 46 A, and at 70 °C to 45 A.
Dimensions are 130 mm height, 76.2 mm width (3 inches), and 70 mm depth.