Polar Pro Quartzline 67mm ND1000 Filter

QuartzLine filters are made of 99.9% pure fused quartz for unrivaled durability and optical clarity. These single lens element, fused quartz filters produce a very low refractive index of 1.46 and offer outstanding temperature stability. The over-engineered brass filter frames thread on smoothly and are built to withstand your most rugged adventures.

Price: £ 229.99 from Wex Photo Video