This is a 18" professional Proven Part brand sprocket nose guide bar that is .325 pitch, .050 gauge and uses a 68 drive link chain.  This guide bar works on Stihl models like the 023, 023C, 025, MS192, MS193, MS200, MS210, MS220, MS230, MS250 & MS251 plus more. Includes .325 Pitch .050 gauge 68 DL Chain  IMPORTANT: Your saw must be equipped with a .325 pitch sprocket for this bar to work on your saw. Some of these models were quipped new with 3/8" pitch sprockets.