I cracked the plastic BBUN54 left cup while tightening and replaced it with this aluminum cup. It fits perfectly, has good quality threads, and feels much more solid than the original plastic piece. It's a bit pricey for such a small part, but it gets the job done. I used some Loctite 242 on the threads and BB body contact surface before installing to prevent accidental loosening. Torque specs are not supplied and ProblemSolvers never responded to my e-mail requesting them. I ended up using the numbers from Barnett's Manual (260-350 in-lbs).