This report is about how a group of U.S. teachers (N = 98) and researchers used a boundary object in a collective study of grades 6-8 mathematics instruction. The focus is the teachers' engagement with a framework for effective instructional practices. Using qualitative content analysis of teachers' responses to use of the framework, we assessed its implementability and usefulness while supporting shared understandings of effective mathematics instruction. We found the framework supported shared understanding and implementation across varied contexts and was viewed as useful for meeting teachers' instructional and professional goals. Constraints were related to ambiguity around understanding and use of instructional practices related to student struggle. These findings demonstrate how a brief researcher-designed framework can serve as a bridge between teachers and researchers, meeting the professional goals of both. [For the complete proceedings, see ED630210.]