Copper Compression Posture Corrector for Men and Women - Guaranteed Highest Copper Back Brace Posture Support Correctors. Adjustable Straightener Maybe a posture corrector? I just got one for my fiancé that looks similar to this they do make different sizes maybe ones that small

Supports Shoulder and Upper Back for Correct Posture https://www.amazon.com/dp/B07MQJXYZL/ref=cm_sw_r_cp_api_glt_fabc_ZYNA5XWVHVAGMFXVFJFZ