The factory fit Steinberger double-ended strings are /horrible/. They have a super-grippy texture which makes them really hard to play. So you're going to want to open up the world of normal bass strings, so you need one of these doodads. Changing the strings is a bit of a fiddle, especially the first time. You need to fit the strings, trim them to length, then take them off. Then trim another few mm, but no more, so that no sharp pokey bits are on the end of your instrument. Then finally refit and enjoy.