Features: Not like common goods in the market, FIRST's converter for press-fit BB (46mm) to external threaded BB (1.37" x 24T) is with patented structure for easy assembly and disassembly by simply loosening the bolts with allen key which is not disposable any more. At the same time, the frame (BB shell) can be protected from being damaged. Specifications: • Converter for Press-Fit BB (43mm) to External Threaded BB (1.37” x 24T) • Compatible for BB Shell I.D. 46mm and Width 68mm~73mm • Patent Pending