yonex mavis 350 yellow slow speed nylon shuttlecock yonex slow speed shuttlecock are usually used in area that are in higher elevation. it is also used by coaches to train strength of stroke and for building stamina (longer rally) to train muscles on the arms. the mavis 350 is one of the best yellow nylon/plastic shuttlecock. it is an easier shuttle to see and play when the wall or surrounding is white. it has the closest performance to feather shuttlecock in flight and feel.