Polarised Sunglasses 🔆
Best way to describe a polarised filter is this; Picture a microscopic sized barcode. Now make it the size of a lens while keeping the lines/bars spaced out microscopic-ly 🤗. Now, embed that filter into a lens. Now when (reflected) glare comes at your eyeball in a horizontal wavelength (its science ok?)...that vertical barcode style filter blocks that particular glare from getting through and making you squint. Embedding a filter in a lens is tough work...so that's why they cost more, k?