Vintage SHIMANO 515 Light Action SL-MS55 Mountain Bike Thumb Shifters Set 1980's | 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
Vintage Shimano SIS Shifters 3/6 Speed Index NOS (483) | eBay