Editorial Review Birch shafts (5/16 diameter) and double-stitched 100% synthetic yarn for maximum durability and weather resistance.M260Soft. Superior for rolls and agile enough for rhythmic clarity in the lowest register. L = 16 M261Medium soft. Produces a huge low-endsound while creating clarity in the bottom two octaves. L = 16 M262Medium. Beautiful tone with medium articulation up to the top octave. L= 16 M263Medium hard. Great tone and clarity through the entire range of the marimba. The most versatile marimba mallet in this series. L = 16 M264Hard. Built to be fast, articulate and havea comfortable weight. Perfect when looking for clarity in upper 2 octaves. L = 16 Get your Vic Firth Ian Grom Signature Synthetic Yarn Mallets w/Birch Shafts today; with the security of our many decades of experience and Sam Ash Direct efficient order processing, your satisfaction is guaranteed!