Seeking extra low-end for your Shimano 1x11 drivetrain' Look no further than the massive 45t cog of the Wolf Tooth Components Giant Cog for Shimano 11-speed. This 45-tooth Giant Cog adds additional low-end range to your 11-speed Shimano cassette (both 11-40t and 11-42t versions), making easy work of spinning up the steepest climbs without tiring out or wasting excess energy. This is especially helpful if you've just converted to 1x drivetrains and miss the "granny gear" of your old 2x set-up. It includes an 18-tooth cog that replaces both the 17 and 19-tooth cogs to make room for the 45-tooth Giant Cog, as well as providing smooth transitions in your higher gears. Please note, its recommended, but not required, to use to Goatlink with Shimano derailleurs for less free chain length and crisper shifting. However, it does work with all SRAM 11-speed rear derailleurs without the need for the Goatlink.