The HSN (Harmonized System of Nomenclature) code for hair straighteners falls under heading 8516. This heading includes electric instantaneous or storage water heaters and immersion heaters; electric space heating apparatus and soil heating apparatus; electro-thermic hair-dressing apparatus (for example, hair dryers, hair curlers, curling tong heaters) and hand dryers; electric smoothing irons.
Here's a breakdown:
85: Electrical machinery and equipment and their parts; sound recorders and reproducers, television image and sound recorders and reproducers, and parts and accessories to such articles
16: Electric instantaneous or storage water heaters and immersion heaters; electric space heating apparatus and soil heating apparatus; electro-thermic hair-dressing apparatus (for example, hair dryers, hair curlers, curling tong heaters) and hand dryers; Electric Smoothing Irons.
Specifically, hair straighteners can be classified under:
8516.32: Other hairdressing equipment
For GST purposes in India, the GST rate for goods classified under HSN code 8516.32 is generally 18%.