One inch diameter nylon with 3/8" hole or tad smaller so a tap fit on,,offer up cover to get correct length so is held firmly in position with cover. This is the longest lasting buffer to date as it's done Route 66,once round Tasmania and twice up & down NZ riders rally & lastly NZ annual with a lap around South Island and half lap round North Island nearly 7k miles. still not returning with a metallic sound.
bananaman