Next Return Previous

(#1961, 2151)

Front View: Closed Rear View: Closed
Front View: Closed Rear View: Closed
Front View: Open for Rigging Rear View: Open for Rigging
Front View: Open for Rigging Rear View: Open for Rigging

Technical Details

I acquired my SOB from Xuefei Liu in 2013. I acquired another in 2017 as part of Bob Thrun's collection.

The ascender shell is a subtriangular orange anodized aluminum stamping 3.4 mm. thick. The rope channel is formed by bending the right side of the ascender into a U. The rope channel is 17 mm. in diameter. Two indentations in the stamping extend from the back of the ascender around the rope channel; these would serve to strengthen the rope channel against unrolling. The main sling attachment point is located below the cam and behind the rope channel. A second attachment point is located above the cam and also behind the rope channel. The shell is bent backwards at both points to provide clearance between the attachment slings and the main rope. This accounts for the rather large thickness of this ascender. The lower attachment point measures 23.9 by 19.3 mm. and the upper 20.7 by 15.7 mm. The left end of the shell is bent on an inclined axis to form another U. A hole drilled through both sides of the U accepts a semi-tubular rivet. The cam, cam spring, and a spacer washer are mounted on this rivet. The head of the rivet sits into a stamped depression on the back of the cam, while the roll is exposed on the open side. The pivot is centered 49 mm. from the inside of the rope groove.

The cam is a skeletonized casting. The cam radius, measured from the pivot, increases from 36 to 55 mm. over an angle of 36°, giving a 33° cam angle. The cam has number of small conical teeth, all of which have their axes approximately parallel to the lower surface of the cam. In between the teeth rows are two slots which open to the central vacancy of the cam. The tooth/hole pattern is (4)(1S1.2S2.1S1)(4)(1S1)^4(4). A spring-loaded manual safety bar is mounted on the bottom of the cam. The normal action of the spring holds the safety against the cam. When the cam is opened, the shell interferes with the safety bar, thus preventing opening the cam. If the safety bar is moved away from the cam (opposing the spring), it will clear the shell and the cam will open. At full open the safety can be released and the spring will hold the safety against the back of the shell. This provides a means of locking the cam open. A bent tab on the safety bar assists in operating the safety mechanism

The front is screened with an outline of an up-pointing arrow enclosing the word "UP" and "ROPE ¤10≤Ø≤13" where ¤ is a circle with a dot inside. The rear is screened with a Reading-Is-Dangerous icon, "ABDR," "EN12841:2006B," "CE1282 EN567," and ¤Ø10-13mm - MAX 100kg."

The weight limit ("Max 100kg.") screened on the Handle can easily be
less than the weight of a fully loaded caver.


The SOB is made in China by the Yue Quing Sbeng Bang Electrical Co., Ltd. ( They make a variety of equipment for electrical lineman. The shell of the SOB is sufficiently similar to the Kong-Bonaiti Cam-Clean to suspect it is a copy, but the cam is different in several ways.

In general I feel that this is a well made ascender. All sharp edges have been removed. The cam teeth are rather well done, though not quite as well as some of my older Petzl's. I would polish the upper surface of the cam safety to eliminate a certain "gritty" feel when engaging or releasing the hold-open feature.

The weight limit ("Max 100kg.") screened on the rear of each ascender can easily be less than the weight of a fully loaded caver. Although I know what this means, American courts may not, so I cannot recommend this ascender for heavier cavers or for expedition caving.