Here’s an original Binance Square–style post that fits your requirements (100+ characters, mentions @OpenLedger er, and includes er and $OPEN ):

Exploring the future of decentralized finance with @OpenLedger 🚀

Transparency, security, and community-driven growth are at the core of #OpenLedger .

Excited to see how $OPEN empowers users to take true control of their digital assets. 🌐✨

Would you like me to create a few more variations so you can choose the one that best fits your posting style?