noun
flat elastic; sewing elastic
Refers to flat, ribbon-like elastic bands commonly sewn into cuffs, waistbands, or other garment parts.
このパンツのウエストには平ゴムが入っています。
These pants have flat elastic in the waistband.
手芸店で幅広の平ゴムを買った。
I bought wide flat elastic at the craft store.