Review on SHIMANO SM BH90 Olive Connecting Insert by Brian Olson

New brakes are included from Shimano. So if you shorten the lines for new brakes, you don't need them. But if you decide to shorten the lines again (too long or simply by swapping out for a new bike) you're going to need it. When you cut the lines, do it at the end of the arm where it will be used. Yes, it's true that you can cut the lines and don't need to bleed the lines as long as you follow the procedure and don't touch the lever, tilt the bike, or fiddle with the calipers. Search and you will find step-by-step instructions online.