The Chrosziel 450-R21 double stage matte box mounts easily onto industry-standard 15 mm support rods and perfectly meets the shooting requirements of compact camcorders and digital SLR cameras, allowing you to have better control over light angles and unwanted lens reflections. This matte box features a double stage of rotating filters, a 16:9 mask, two filter holders (one accepting 4 x 4 filters and the other adjustable to accept 4 x 5.65" and 4 x 4" glass filters), a top flag, and a swing mechanism for side flags (sold separately). The Chrosziel 450-R21 double stage matte box also includes a 15 mm rod support and a rear protective plate with 114 + 110 mm threading. Top Flag Controls the angle of light and eliminates unwanted lens reflections and flare, and can be paired with optional side flags for precise light adjustment.