The XLC Y-key TO-M15 is a great addition to any toolbox. The Y-key is a three-in-one tool consisting of a 4 and 5mm hex key and a T25 Torx key. On most modern bikes, you can tighten bolts, such as the stem, seat post, and headset clamp, with this key. Compact enough to take with you while cycling or to store in a small garage with limited space. Three-in-one tool: 4mm, 5mm, T25 XLC Article number: 2503607900 EAN code: 4055149116262 Retail packaging: Yes