The Schneider 4.5" Adapter Ring provides convenient access for Series 9 and 4.5" drop-in filters. Schneider Direct Screw-on Adapters, sometimes referred to as step-up rings, are mounted directly to the front thread of the lens and provide access to a universal or larger-size round drop-in filter.
It should be noted that to facilitate the use of drop-in filters on threaded and unthreaded lens barrels, Schneider also introduced the Set-Screw-Lock Ring Adapter (SSLR). Both Adapter Rings and SSLRs are precision manufactured using high-grade aluminum and are coated with a black anodized finish.
4.5" Adapter Ring