repère de virage de dos
/kʁonomˈɛtʁ elɛktʁonˈik otomatˈik/
n
English: backstroke turn indicator · 仰泳转身标志绳
Sens：Rope with pennants that is strung 5 m from the finish and turning walls; backstroke swimmers use it to judge distance.
English: backstroke turn indicator · 仰泳转身标志绳