Maco Drive Internal Drive Gear
gr1 ffh 500 - 650 No Rollers
gr2 ffh 651 - 900 No Rollers
gr3 ffh 901 - 1300 1 Roller
gr4 ffh 1301 - 1800 1 Roller
gr5 ffh 1801 - 2350 2 Rollers
All 16mm Back Set
* Note these gears have the same teeth as Gu and will connect to some Gu corner drives