Just weighed the one supplied with the Big Bro Frame and it's only 20g. But it's quite a cheap looking thing. I notice they do a chunky CNC machined one with a lazer engraved logo. It's not Orange though...
https://www.brothercycles.com/shop/accessories/oak-leaf-seat-clamp/
https://www.brothercycles.com/shop/accessories/oak-leaf-seat-clamp/