This is a Treadmill Doctor Replacement Rear roller Part Number K140043-Z3 for Various Sole and Spirit Treadmills Listed Below.

Sole-
2009-2010 Series - WF80 (580888)
2011 Series - AF85 (585810)
2013 Series - F80 (580812)
2013 Series - F85 (585812)
2013 Series - S77 (577812)
2014 Series - F80 (580812)
2014 Series - F85 (585812)
2014 Series - S77 (577812)
2018 Series - F80 (580818)
2010-2011 Series - S77 (577810)
2016 Series - F85 (585816)
2016 Series - S77 (577816)
2016 Series - F80 (580816)
F85 - 585818 

Spirit -
X Series Treadmill - XT285 - 2013 Ver. 2 (After SN 2858121212000001)
X Series Treadmill - XT385  
2018 Series - S77 (577818)