备用环

backup ring

variant of 備|备[bei4]

to prepare / get ready / to provide or equip

(bound form) to prepare; to equip / (literary) fully; in every possible way

reserve / spare / alternate / backup

to use / to employ / to have to / to eat or drink / expense or outlay / usefulness / hence / therefore

surname Huan

ring / hoop / loop / (chain) link / classifier for scores in archery etc / to surround / to encircle / to hem in