Sill extensions are additional parts that are attached to a window or door frame to make it longer, as a way to cover a larger opening. Full definition
Features include larger air dam, fog lamps, multi-spoke alloy rims, side sill extensions with side decals, red brake calipers and chrome bezels for the bug - eyed headlamps. (indianautosblog.com)
At the side, this includes the door mirror housings in «matt chrome», the side sill extensions with «R» styling and the brake callipers painted black with «R» logo. (topspeed.com)
New sill extensions seamlessly bridge the gap between the widened arches. (ausmotive.com)