Daytona Twin Tec TC88A Plug-in Ignition for Harley Davidson 2004-06 Twin Cam/Sp Wide timing advance adjustment range accommodates stock to highly modified engines Digitally set rpm limit (100 rpm steps from3,000 to 9,900 rpm) Full support for j1850 data bus used for communications with instrument cluster and turn signal/security module (tsm/tssm) Built-in data logging. stores last 30 minutes of engine operation Extensive diagnostics. compatible with h-d scan tool