Amazon.com : Shimano Tourney Original RD-TY300 6/7Speed Rear Derailleur SIS Direct Mount : Sports & Outdoors
SHIMANO SIS RD TY22 VINTAGE REAR DERAILLEUR FITS SCHWINN MURRAY & OTHER NOS | eBay
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 deraileur(5 Speed) to Tourney(6/7 Speed) : r/bikewrench