Sister Sizing is an alternate bra size. Simular but not the same

Sister Sizes: The Bra Secret Every Person Should Know – Sister Sizes & Equivalent Bra Size Chart – ThirdLove

Sister size Bra size charts, Correct bra sizing, Sister bra sizes

What is my bra size?

DD Cup Bra Sizes DD-mystified – Harlow & Fox

Sister Sizes: The Bra Secret Every Person Should Know – Sister Sizes & Equivalent Bra Size Chart – ThirdLove

Sister size, Bustyresources Wiki

They Don't Have Your Bra Size? Try Your Sister Size for a Great Fit

Sister Sizing De-Mystified! – Playful Promises

Sister Sizing 101