snippet: <p><strong>13445-304, Replacement peek spring for 6mm shaft, fits 13445-06 and -09 bearings </strong> </p> <p>Debris-free PTFE stirrer bearing totally eliminates flaking into the reaction. Vacuum tight and chemically resistant. 500rpm maximum with polished glass or stainless steel stir shafts. Not recommended for use with precision ground or PTFE covered, stainless steel shafts. </p> (Page 1)