What are they called and is it specific to that shifter?
Shimano call it a lever boss cover, and they are pretty agnostic with respect to the levers (assuming Shimano SIS) but there are two curvatures, a small one for 1.125" steel down tubes and a large one for aluminium/oversized. e.g. https://www.sjscycles.co.uk/gear-spares/shimano-sl6028-lever-boss-cover-for-alloy-frames/
Much thanks @mdcc_tester!
Just beware that the ones he linked to are the flat-backed ones for Vitus 979s etc.
@Thrust started
London Fixed Gear and Single-Speed is a community of predominantly fixed gear and single-speed cyclists in and around London, UK.
This site is supported almost exclusively by donations. Please consider donating a small amount regularly.
Shimano call it a lever boss cover, and they are pretty agnostic with respect to the levers (assuming Shimano SIS) but there are two curvatures, a small one for 1.125" steel down tubes and a large one for aluminium/oversized.
e.g. https://www.sjscycles.co.uk/gear-spares/shimano-sl6028-lever-boss-cover-for-alloy-frames/