The 38mm B2-FAB Screw-Knob Clamp from Really Right Stuff is an Arca-type compatible clamp with laser-engraved 1mm scales on each side of 38mm long jaws, so a camera can be aligned within the quick release.

The screw-knob style clamp features a rosette design for secure mounting to compatible ball head and other devices. A legacy tongue-and-groove adapter is available separately. A 1/4"-20 threaded female socket enables the clamp to attach to a monopod or tripod without a quick release. This clamp is constructed using black anodized aluminum.

Arca-Type Compatible Clamp    38mm Long Clamp    Screw-Knob Style Closure    Rosette Mounting Base    1/4"-20 Threaded Female Socket    Laser-Engraved Scale in 1mm Increments

Related Questions and Answers

Q: 1. Does the diameter of the shaft extend below the bottom plane, like some of the cheaper clamps that people have complained about?

A: The Really Right Stuff B2-Pro-II 60mm Screw-Knob Pro Clamp (B&H# REB2PROII) is made with exacting precision and it will fit the intended heads without having any problem like the one you mentioned: Really Right Stuff ball heads Arca-Swiss current model ball heads Manfrotto 468 ball head Manfrotto 468RC2 ball head Manfrotto 488RCO ball head Manfrotto 469 ball head Manfrotto 469RC ball head

Q: 2. Will this fit the Manfrotto 494 Ball Head?

A: No, the Really Right Stuff B2-FAB 38mm Screw-Knob Clamp will not fit onto the Manfrotto 494 Center Ball Head with Universal Round Disc Mount.

Q: 3. What is the diameter of the top plate?

A: The manufacturer does not mention this information. This is a Arca Swiss mount so you will need a Arca style plate for compatibility. https://bhpho.to/3q0MG1v

Q: 4. Can this be mounted on a monopod. Then attach the wimberly monogimble?

A: The Really Right Stuff B2-Pro-II 60mm Screw-Knob Pro Clamp can be attached to a monopod. The Wimberley MH-100 MonoGimbal Head for Monopods has a 3/16"-16 threaded socket and an Arca-Swiss Style dovetail. You could use the TTS clamp, but it is not required to use the Wimberley MH-100 MonoGimbal.

Q: 5. Can I mount this to a video tripod, like a Sachtler or Miller?

A: Whether you can mount the Really Right Stuff B2-Pro-II 60mm Screw-Knob Pro Clamp on your existing head will depend on the connecting method on your head. This clamp features one threaded 3/8"-16 recessed center socket flanked by two threaded 1/4"-20 recessed center sockets, the RS-Pro-II can be mounted from beneath directly on a tripod head platform, or from above using 1/4"-20 or M6 screws.

Q: 6. Are the two clamping jaws of this clamp strong enough to securely hold a variety of equipments?

A: Yes Really Right Stuff B2-Duo Sliding Screw-Knob Clamp (60mm) jaws are strong enough to hold a variety of equipment.

Q: 7. Can this be used on the Manfrotto BeFree? Will the legs still fold properly?

A: With a reducer bushing purchased separately you can fit it on the top of the quick release plate that comes with your tripod but if you do that you will have two different clamps. You may end up sometimes opening the wrong clamp accidentally. If you want an arca clamp to a Manfrotto Befree tripod I would recommend this adapter from Manfrotto. If you use this you will only have one clamp. Please make sure your tripod head is listed as compatible in this listing. It is small and shouldn't affect the folding of the legs. https://www.bhphotovideo.com/c/product/1484861-REG/manfrotto_msq6t_top_lock_travel_quick.html

Q: 8. Is this compatible with Manfrotto MHXPRO-BHQ2?

A: You may consider purchasing the Desmond DBAD Female to Male Boss Adapter for Select Manfrotto Heads, B&H # DEDBAD, to connect the Really Right Stuff B2-Pro-II 60mm Screw-Knob Pro Clamp to the Manfrotto XPRO Magnesium Ball Head with 200PL-14 Quick Release Plate.

Q: 9. Will this fit on a IFootage Cobra 3 C180F-P?

A: Yes, the Really Right Stuff B2-Pro-II 60mm Screw-Knob Pro Clamp can screw into the Really Right Stuff B2-Pro-II 60mm Screw-Knob Pro Clamp.

Q: 10. Will this fit on the IFootage Cobra 3 C180F-P?

A: Really Right Stuff B2-mAS Screw-Knob Clamp has a 1/4"-20 female screw and iFootage Cobra 3 Carbon Fiber Monopod with Pedal-Release Mini Tripod Base has a 1/4"-20 Male screw so it should screw in. If you need any help, please feel free to start a live chat during business hours. An expert from our Pro-Photo department can virtually guide you over live video in the store. https://bhpho.to/3MLX2vU