hoya filter weight
They use regular optical glass and weigh 34.4g in 77mm size, with a 5.4mm thick mounting ring. The Pro-1 polarizers lose 1 2/3 stops of light and come in 52mm, 55mm, 58mm, 62mm, 67mm, 72mm, 77mm and 82mm. The Nikon is a better filter at about the same price, but doesn't come in all the sizes that the Hoya Pro 1s do.