light tight vent louvers lite tite

There are a few lite-tite louvers out there, but expensive at $30 for an 8x8. https://www.bhphotovideo.com/c/product/43104-REG/Doran_PRDV99_DV_99_8x8_Light_Tight.html There are a few good DIY vent threads out there: https://www.icmag.com/ic/showthread.php?t=164913...