This RRS B2-mAS Screw-Knob Clamp 1/4"-20 38mmfrom RRS B2-mAS Screw-Knob Clamp 1/4"-20 38mmis designed to mount to the top of tripods, monopods, or video fluid heads that do not have a quick release system. The clamp is CNC machined 6061-T6 aluminum and has a black anodized type II finish. It features a laser-engraved scale in 1mm increments for precise positioning. The screw-knob clamp will mount to any tripod, monopod, or head with a 3/8"-16 screw, or a reducer bushing can be utilized to fit 1/4"-20 studs. The base of the clamp features a rosette design for secure mounting to compatible ball heads and other devices, and will prevent twisting at the coupling point between the clamp and head over time. A legacy tongue-and-groove adapter is available separately.

Arca-Type Compatible Clamp    Laser-Engraved Scale    CNC Machined 6061-T6 Aluminum    Type II Black Anodized Finish

• Arca-type compatible clamp

• Adds quick release functionality to a tripod or monopod

• CNC machined 6061-T6 type II anodized black aluminum

• Laser-engraved scale in 1mm increments

• Rosette style mounting base

Related Questions and Answers

Q: 1. 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: 2. how wide are the three strap bosses? Will a 1" strap fit?

A: The side lugs of the Really Right Stuff B2-FABN Screw-Knob Clamp with Strap Bosses (38mm) will fit a 0.70" strap, the front lug is 0.98" max, and both are 0.125" thickness maximum.

Q: 3. Thank you everyone for your response. But I'm still wondering: if I mount this on a flat surface, and that surface extends out past the bottom of the clamp (not to the knob, of course), does the diameter of the shaft allow for clearance so the clamp sits firmly on the flat surface? Sometimes I use clamps on something other than ball heads. Thanks again.

A: Yes, the bottom surface of the Really Right Stuff B2-Pro-II 60mm will seat flat on the camera support plate system similar to BH #PLPMPMT1009. However, the knob can not be under the same plate surface because it's larger than the clamp high. The knob is 25mm while the plate is only 18mm. I will recommend the BH #REB2LRII with the Level since this part is the same high as the clamp and won't interfere if you place your plate on a flat surface.

Q: 4. I want to mount this on the top, moving rail of a Manfrotto 454 Macro Focusing rail to accommodate a l-bracket attachment of the camera body. Does the tightening knob clear the bottom of the clamp when mounted on a flat surface? Also, will the anti-twist tabs fit into the 1/4" slot in the 454 top rail?

A: Good question. Thank you. There is not enough clearance to accommodate functionality of the knob when attempting to mount it with the anti-twist tabs into the 1/4 20 slot.

Q: 5. What's the distance between the two outer mounting holes? I wanna mount this plate on a 322 ball head.

A: The two outer mounting holes on the RRS B2-Pro II 60mm Screw-Knob Pro Clamp are 30mm apart.

Q: 6. 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: 7. 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: 8. Can this clamp be mounted on another clamp to be used to change the direction of the rail's orientation?

A: Yes, this is possible, but depending on what equipment you plan to mount and the knob size on the other clamp, there could be interference, though many configurations should work.

Q: 9. 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: 10. 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.