Yamaha marching Tuba & Sousaphone (& others) OEM Valve Guide Set of 3 or 4 - G0141093 guides, if in doubt, email me with your model.  For the smaller Baritone and marching euphonium, see my item ID# .Fits:YBB-100SYBB-103(2)YBB-103S(2)YBB-104YBB-104SYBB-105YBB-105MYBB-105MSYBB-105SYBB-110SYBB-201(2)YBB-201MYBB-201MSYBB-201S(2)YBB-202MYBB-202MSYBB-321(2)YBB-321S(2)YBB-621YBB-621SYBB-631YBB-631SYBB-632YBB-632SYCB-621YCB-621SYCB-822YCB-822SYEB-201YEPYEB-201MYEB-201MSYEB-201SYEB-321YEB-321SYEB-381YEB-381SYEB-631SYEB-632YEB-632SYEP-100SYEP-100SAYEP-201(2)YEP-201MYEP-201MSYEP-201S(2)YEP-211(2)YEP-211S(2)YEP-321(2)YEP-321S(2)YEP-621(2)YEP-621S(2)YEP-641(2)YEP-641S(2)YEP-642YEP-642(NEO)YEP-642SYEP-642S(NEO)YEP-642TYEP-642TSYEP-842SYEP-842TSYFB-621YFB-621SYFB-822YFB-822SYSH-301(2)YSH-301(3)YSH-301S(2)YSH-411YSH-411S