This ARRI R2 138mm Filter Ring fits into the back of ARRI matte boxes with a rear opening of 143mm, and is for internal focus lenses only. It enables mounting a 138mm round filter, such as a polarizer, onto your matte box and allowing for rotation of the filter. The R2 ring acts as an anti-refection donut and supports lenses with a front outer diameter of 114mm such as Master Primes, Ultra Prime, and LDS Ultra Primes.

The ring will allow you to use wide-angle video lenses as well, but only lenses with an internal focus design. It will accept optional R4 reduction rings, which allow you to use select lenses with a front outer diameter of less than 114mm.

• For matte boxes with rear 143mm opening. Compatible with the MMB-1 top-loading matte box
• Anti-reflection donut accepts 138mm round filters
• This R2 ring works with internal focus lenses only, as it does not accommodate the expansion and contraction of external focus lenses
• For lenses with a 114mm front outer diameter
• Accepts R4 reduction rings for working with lenses that have a smaller front outer diameter than 114mm