Ankur003
UltraWideLife.com
http://www.bhphotovideo.com/c/product/811292-REG/Hitech_HT150NDRG0_9_4_x_6_Reverse.html@Ankur003 please provide any links to buy that type of square filters.
I cant find many options right now but have seen many people using square (100x100) GND filters.