Description Specs Compatibility Product Highlights: • Hardened Anodized Aluminum Design • Precise Thread for Smooth Mounting • Standard Filter 0.75 Pitch Size • Silver Finish to Match Lens & Filters • Limited 2-Year Manufacturer Warranty Fotodiox step-up rings are precision crafted from aluminum-alloy for durability while remaining lightweight. Every ring is inspected to ensure smooth mounting. Every ring is polished and finished with anodized matte surface for professional appearance. This step up adapter ring set allows a filter/attachment with larger thread size to be used with a lens with smaller thread size. Back to Highlights Material Silver Anodized Aluminum Thread Pitch 0.75mm Shipping Dimensions 5 x 7.5 x 1.5 in (12.7 x 19.1 x 3.8 cm) @ 0.2 lb (3 oz) Manufacturer Fotodiox Inc. Warranty Limited 24-Months All pictures are for illustration purposes only. Actual product may vary slightly due to ongoing improvements in design. • Bay II is the mount for the f/3.5 Planar and Xenotar • Bay III is the mount for the f/2.8 Planar and Xenotar • Bay III is the mount for the Tele-Rolleiflex with 135mm f/4 Sonnar • Bay IV is the mount for the Wide-angle Rolleiflex with the 55mm f/4 Distagon