Amazon.com : Rear Derailleur, Huazu Bike Parts Gear Shifter for Shimano RD-TZ31-A with Direct Mount/Hanger Mount for 6/7 Speed Mountain Bicycles : Sports & Outdoors
New 7 speed commuter with Shimano SIS index. No noise on stand, shifts smoothly but low clanking sound on road when pedaling in 4th & 5th though not other gears : r/bikewrench
Shimano Sis Index 6/7 Speed Rear Mech - Bike Parts Weston