B2-MAS: 38MM Screw-Knob Clamp


Discover the B2-MAS mini-clamp by Really Right Stuff, a quick-release system for secure camera mounting.

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The B2-mAS mini-clamp has one counter-sunk clearance socket allowing a 1/4"-20 screw to securely mount the clamp to an RRS ballhead or other accessory fit with the male component of our patented R-Mount anti-twist, indexing rosette interface. 
Why should you invest in a quick-release system? Because screwing your camera or lens onto a platform with standard 1/4"-20 screw is tedious and insecure. Not only is it a hassle to screw your gear onto that platform, but once installed the camera or lens is free to rotate; there's nothing to prevent it from coming loose. Why invest your money in a tripod and tripod head only to compromise your shots with an insecure connection between camera and head? Instead, adopt the Really Right Stuff quick-release system.

The Really Right Stuff quick-release system is perfectly compatible with all equipment made to the RRS Dovetail Standard (the most broadly accepted standard accross multiple industries) and is compatible with most Arca-Swiss style plates. It has two parts: a quick-release clamp and a quick-release plate. You always need both pieces of the system. The clamp will stay on your tripod head/accessory all the time, and the plate will stay on your camera all the time. You will need to purchase a separate quick-release plate for each camera or collared, telephoto lens that you want to mount in the quick-release clamp on your tripod head.

Clamp jaws open and close in one of two ways: by twisting a knurled knob on our tried & true screw-knob clamps; or by flipping a single lever on our innovative, patented lever-release clamps. Traditional screw-knob clamps are tried & true and can deliver slightly greater clamping force than our Lever Release clamps.

Mini-clamp with 3/8"-16 countersunk threaded socket, 38mm jaws. The B2-FABN mini-clamp has one 3/8"-16 threaded socket for screwing onto a 3/8"-16 threaded post or stud and comes with flat head 1/4"-20 mounting screw for attaching to a threaded female 1/4"-20 socket.


  • The B2-mAS (as in mini-AS clamp) can be mounted with a flat head screw on mini-ballheads with a threaded female 1/4"-20 socket, or onto a threaded 3/8"-16 stud.
  • Please note, the 3/8"-16 threads of the B2-mAS are very shallow (only about 2.5 threads) and should not be used in heavy-weight applications.
  • Need a sliding clamp platform? The B2-mAS can be mounted back to back with our B2-FAB mini-clamp using a flat head screw when you need a double-sided clamp, such as our Mini Clamp Package. The tabs on the bottom of the B2-FAB allow it mount in the recessed "cross" on the bottom of the B2-mAS without twisting.
  • Made for minimal clearance and minimal weight and compact size, the knob of the B2-mAS mini-clamp bears directly against the clamp jaw and is "captive" can't be lost in the field.


Country of Origin: USA
  • Jaw Length: 1.5" / 38mm
  • Width: 2.9" / 74mm
  • Height: 0.6" / 15mm
  • Weight: 2.3 oz / 64g

In the Box

(1) B2-mAS screw-knob  clamp
(1) Flat head screw, stainless steel, 1/4"-20 x 3/4"
(1) Flat head screw, stainless steel, Metric 6
(1) 5/32" hex-key
(1) Rosette Adapter (for RRS Tongue and Groove Ball Stems)
(1) User's guide


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