In size of 3mm, it suits small duct earphones as the following:
SHURE: E1C, E3C, E3G, E4C, E4G, E5C , E5SCL3 , SCL4 SCL5, SE110, SE210, SE310, SE420, SE530(E500), SE115, SE215, SE315 , SE425, SE535;
Etymotic: ER6I , ER4P , ER4S, MC5, HF5;
Westone: UM1, UM2, UM3X, W1 , W2, W3, W4, W4R.