This line of mallets is designed with durability, projection and tone quality in mind. Each marimba model has a hard rubber core with the weight to fill any stadium with the warmest fundamental tone possible. The wrap, used exclusively for the marimba mallets, is a special tightly woven multi-ply wool with proven strength and durability. Each of the vibraphone mallets has a mushroom shaped rubber core wrapped with a multi-ply cord and is constructed to withstand the conditions of daily outdoor rehearsal and performance. Marimba FS150, FS250, FS350R & FS350 Hard rubber cores for full, rich tone and warm fundamental; increased weight for add projection; highly polished birch or rattan handles. Vibraphone RFS320 & RFS420 Hard rubber cores, extra durable rattan handles and tightly woven multi-ply cord for strength and durability. Xylophone/Bell FS550R, FS550, FS650R & FS650 Increased weight for added projection; thick, highly polished birch or extra durable rattan handles; 100% hand crafted.