We present the first stable release of our tool Q3B for deciding satisfiability of quantified bit-vector formulas. Unlike other state-of-the-art solvers for this problem, Q3B is based on translation of a formula to a bdd that represents models of the formula. The tool also employs advanced formula simplifications and approximations by effective bit-width reduction and by abstraction of bit-vector operations. The paper focuses on the architecture and implementation aspects of the tool, and provides a brief experimental comparison with its competitors.