The HOYA's Sq100 square filter system aims to give photographers the means and freedom to fully express their creativity and to realize their artistic goals to the fullest. The Sq100 square filter system comes with many advantages:

• Adapter rings for various sizes allow the photographer to use the system with a wide range of lenses with all kinds of thread sizes. This makes the square filter system a great long-term investment, as it is not necessary to buy the same filter multiple times for different sizes.
• As square filters are usually larger than the front glass element of the lens, the chance for vignetting is reduced to a minimum, even when stacking filters.
• Stacking filters is more effective with a square filter system as it can carry up to three square filters in addition to the polarizer. Switching filters is faster and easier than with stacked round filters.
• Filter holders can be rotated, giving the photographer the option to reposition the line of graduated ND filters. The line can also be adjusted vertically with a filter holder.
• The HOYA Sq100 square filter system features a sophisticated filter holder kit and a line of high-quality filters, making it a recommendation especially for advanced and professional photographers in the field of landscape and cityscape photography.

HOYA SQ100 holder kit
The Sq100 holder kit includes a holder, a polarizer and two geared adapters that fix the polarizer inside the holder and attach it to the lens. The holder's precise slot system can carry two square filters in addition to the polarizer with an optional slot for a third square filter (included in the kit). The body is made of aluminum for optimal durability while being still light-weight. A black gasket on the edge of the inside holder ring as well as a gapless design of the slots minimize light leak.
The holder with the attached filters can be rotated, giving the photographer more creative opportunities, such as adjusting the border angle of a graduated ND filter.
The circular polarizer can be rotated inside the frame for perfect reflection and saturation control. With its large diameter of 86mm, the polarizer filter won't cause any vignetting with most lenses. HOYA's special water repellent multi-coating is applied to the polarizer's optical glass, making cleaning easy and stress-free.

The polarizer adopts a high transparency polarizing film for fast shutter speed. This translates to no less than nearly 1/2 stop more light entering the lens while yielding the same polarization effect. An absolute must for shooting in low light conditions

How to attach
For using the polarizer, screw it into the geared adapter and attach the geared adapter to the lens. When attaching the Sq100 holder to a lens with an 86mm filter size, use the 86mm-86mm geared adapter. When using the system with an 82mm filter size lens, use the 86mm-82mm geared adapter. For other lens sizes, use the adapter rings which are available in all common sizes.