The all The S5 has an intergrated polariser and filter slots for 2 150mm filters. 
I have been using this system for about a month and love it! Here is a link to a video I made. https://youtu.be/pKwoJWnRwR8
The NiSi S5 Kit 150mm Filter Holder with CPL for Tamron 15-30mm F2.8 & Pentax 15-30mm F2.8 is ideal for landscape photographers who wish to combine an ultra wide angle lens with a filter system. The S5 filter holder system is constructed with aluminium alloy utilising CNC technology. It allows the use of an integrated PRO CPL and 2 150mm filters without vignetting throughout 360 degrees of rotation. It is a new 150mm filter system which includes a multiple model adapter to allow use with selected ultra wide angle lenses.
A geared design allows the integrated CPL to be rotated while using 150mm filters using two gear located on the rear of the holder, a design feature taken from our leading V5 Pro holder.  The holder allows very quick installation and removal without removing the lens from the camera.  The front of the holder with clips holding the 150mm filters can be rapidly removed to allow focus and easy replacement or removal of the filters.
The kit includes the holder, adaptor mount for the 15-30mm, a NiSi Pro C-PL and a case to store the holder.
THE S5 WILL SAY TAMRON ON THE HOLDER IN VERY SMALL PRINT.