Costa 580P is polycarbonate and 580G is glass. What 580 means, how they differ on weight, clarity and scratches, what each costs, and which one to buy.
KastKing is cheaper up front; Wavy adds a lifetime warranty (a flat $30 fee gets you a new pair) and amber freshwater tuning. An honest budget fishing-sunglasses comparison.
Defect-only or flat-fee replacement? What a lifetime warranty on fishing sunglasses usually covers, what to check, and how Wavy's $30 new-pair replacement works.