NEW DESIGN High Yield Reset Lever Gear with Spring for use in Brother TN-660. For the first time in history, Brother has made 2 versions of the same cartridge. Brother toner cartridges (TN660 model) prior to about January 2017, use a different internal gear and have a slightly different design than the Brother cartridges (also TN660 model) that were released after about Jan 2017.
How do you tell the 'old design' cartridge from the 'new design' cartridge?
The 'old design' cartridge has a round fill plug on the side of the cartridge. If your cartridge has a fill plug, you have an 'old design' and you need the 'old design' reset gear (only needed for starter cartridges).
The 'new design' cartridge does not have a fill plug on the side of the cartridge. If you have a 'new design' cartridge, you need the 'new design' reset gear (only needed for starter cartridges). You will also need a toner hole making tool to make a hole to refill your cartridge, since it doesn't have a fill plugport.