It appears to be either a C-Channel or a Box-Channel.
From the information gathered at this manufacturer's reference, it appears that you'll need to identify a few more characteristics of the beam before you can determine its properties.
Here's a sample image and expected specifications for box channel from that previous reference. This would be a cold rolled section made of light gauge sheet metal.
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There is also hot rolled C-channel, which has a different shape.
And some sites will provide properties for standard sizes of that channel.
It's hard to tell from the image, but it appears to be rectangular tubing, so the 150 is likely millimeters and is the channel height. You'll either need to provide more information or perform additional research on your own in order to determine what the 100 and 40 values refer to.