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Edelweiss MicroB

Front Rear Top
Front Rear Top
Front: Open for Rigging Rear: Open for Rigging Bottom
Front: Open for Rigging Rear: Open for Rigging Bottom

Technical Details

I acquired my Edelweiss MicroB from Buffalo Gap Outfitters in 2021.

Cam faceThe Beal Tract Up is 34 mm. tall, 66 mm. wide, 31 mm. thick, and weighs 86 g. The body of the Tract Up consists of an aluminum alloy spool crimped to a 3.9 mm. aluminum alloy plate. The spool’s outer diameter is 26.7 mm., and a shallow U-shaped groove reduces the diameter to 24.9 mm. where the rope rides. The inside of the spool is 18.1 mm. in diameter. The rope channel is 15.3 mm. wide.

The cam axle is riveted to the back plate, with a steel washer under the riveted head protecting the aluminum plate. The cam is spring loaded, but the spring is not visible. A small roll pin pressed into the back plate probably forms a bearing surface for one end of the cam spring. The cam axle is about 6 mm. in diameter (I would have to destroy the ascender to get an accurate measurement). The axle is centered 26 mm. from the inside of the rope channel. The cam radius increases from 17 to 25 mm. over an angle of 102°, giving a 13° cam angle. The tooth pattern is (ZZ)^3(Z).

The front plate is made from 3 mm. aluminum alloy. A 23.3 mm. hole lines up with the spool and back plate holes. When closed, the hole encloses a rim on the spool. The cam axle has a rubber washer outside the front plate that acts as a spring to force the plate toward the back plate.

The front plate is printed with "microB," "8-11 mm," a curved line with an up-pointing arrow at the center and a ring anchor at the top, and edelweíss. The rear plate is printed with a book-with-an-"i" icon, "0179•11/20," the U.I.A.A. logo, "EN567:2013," and "CE 0596."


The Edelweiss MicroB has the same body and spool as the Beal Tract Up, but the cam is ddifferent. It also bears a strong resemblance to the Kong Duck.

I find that I need two hands to rig the MicroB. Only the top few teeth engage when I use 11 mm. rope, and the rounded teeth slip under unfavorable conditions. The conical teeth on the Mouse hold better. The clip-in hole is quite close to the main line and is opposite the cam, so there is little lost motion (less than two centimeters) when loading the ascender.