The QRC-40B can be mounted back to back on QRC-40A/55/65 to allow fore-and-aft sliding on Arca Swiss compatible rails such as our multi-functional rails. Two clamps can be mounted with clamp channels running parallel or perpendicular to each other, accommodating both camera plates and lens plates. Removable index marker at the center allows for precise positioning of clamps. Index marker with a thickness of 5.5mm allows for accurate reading of scale up to 0.5mm. Use the edge at the center to read the scale up to 1mm. Use the edge at the side to read up to 0.5mm.

For customers using short ultra-wide angle lenses such as shaved Nikon 10.5mm on full frame camera, a significant portion of MFR-170/210 will block the angle of view of the lenses if the camera is mounted at the normal position of rail. QRC-40B is needed to slide the QRC-40A/55/65 to the inner part of the rail. Double dovetail rail is a pre-requisite in this application. QRC-40B doesn't work with MFR-160. Rail stops can be installed on the rail to limit the range of travel of QRC-40B to nearest cm. NPP setting should be adjusted by the movement of MFR-170/210 relative to the rotator clamp. This is important in order for the integrated rail stop to function and build a consistent database of the settings.
QRC-40B also allows FANOTEC Lens Ring Clamps to be used on NN4. A dedicated mounting kit is needed.

Recommended retail price of QRC-40B is $50.