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Kong Trender
(#1523, 2291)


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 Kong Trender from WesSpur Tree Equipment in 2010. I acquired another in 2017 as part of Bob Thrun’s collection.

The Kong Trender is 220 mm. tall, 181 mm. wide, 51 mm. thick, and weighs 613 g.

The Kong Trender is an evolutionary extension of the Kong Twin , with two ascender assemblies riveted together back to back with a dual handle and a moving safety assembly sandwiched in between.

The ascender assemblies

The front ascender assembly is right-handed and the rear ascender assembly is left-handed. Each shell is a tall irregular shaped stamping made from 3.5 mm. aluminum alloy sheet metal that is later anodized. A rope channel is formed in of one side and a smaller cam channel lies opposite the first. The rope channel is 15 mm. wide. A hole drilled through both sides of the cam channel accepts a 6 mm. rivet. The cam and cam spring are mounted on this rivet, along with a flat washer on the inner side of the cam. A 14.8 by 17.5 mm. oval hole through both sides of the rope channel provide an attachment point just above the cam. Each ascender assembly has 12.5 mm. wide, 10.5 mm. high D-shaped hole above the cam stop, but these are blocked by the moving safety assembly. There is a 13.6 mm.hole punched at the base of each ascender assembly shell, but these are blocked by the handle. Two rivets above this hole hold the ascender assemblies and handle together. There is another 9 mm. hole below the cam channel. This allows the carabiner to hold the moving safety assembly in the down position.

Cam faceThe cam is a painted steel casting. The cam has number of small conical teeth, all of which have their axes approximately parallel to the upper cam surface. The cam radius increases from 37 to 57 mm. over an angle of 43°, giving a 30° cam angle. The tooth pattern is (3)(4.H)^2(3.H)^2(3.3.2) where H is an oval hole. The inner cam face radius reduces from top to bottom to accommodate various sized ropes. A spring-loaded manual safety bar is mounted on the bottom of the cam with a small semi-tubular rivet. 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 tab on the safety bar assists in operating the safety mechanism.

The front ascender assembly is printed with the Kong logo, "ITALY," "TRENDERFULL," and "mod.pat." There are no makings on the rear ascender assembly.


The handle attaches between the two ascender assemblies by the rivets mentioned earlier. The handle is made from 3.5 mm. aluminum alloy. There are no reinforcing ribs. The handle has a 103 mm. by 55 mm. oval hand opening under the ascender assemblies and a 98 mm. by 58 mm. hand opening on the other side. Both openings have "rubbery" black plastic hand grips molded to the sheet metal frame. The handgrips each have four shallow, closely spaced finger grooves. There is a 14 mm. attachment hole near the bottom center of the handle aligns and a 10 mm. hole beside it, on the ascender assembly side.

The top of the hand grip is printed with the UIAA logo, "CE 0426," the book-with-an-"i" two crossed out people, a rigging icon, a person with an "X" on their chest, and SWT 100 kg."

The weight limit ("SWT 100kg") printed on the handle can easily be
less than the weight of a fully loaded caver.

The midstrap is printed with "092049 09 0152," and the following three lines of information:

Safety assembly

The safety consists of a 3 mm. plate with a cross plate welded to it at the top and an 8 mm. ferruled carabiner attached via 1.5 mm. stainless steel cable. The T-assembly slides up-and-down between the two ascender assemblies. When in the down position, it keeps the ropes from coming out of the rope channels. Aligned holes in the ascender assemblies and the T-assembly allow using the carabiner to hold the T-assembly in the closed position. With the carabiner removed, the T-assembly can slide upward, allowing one to insert or remove rope to/from the rope channels. When in this position, a tab on the T-assembly prevents inserting the carabiner.

The carabiner spine is stamped with "KONG ITALY Pat <> MAX 800 KG" where "<>" represents two triangles.


The instruction manual that came with my Kong Trender illustrated several Kong ascenders, but it did not show or mention the Trender, nor did it give any instructions on how to use it.

The Trender is designed as an arborist tool, so I'll let Tarzan evaluate it for that purpose.

Cavers and climbers seldom climb on double rope, so the Trender is less suited for my needs. The Trender is well made, but I find the safety assembly a bit time-consuming to operate. The Trender is also too bulky for my taste - but so are all other dual-handle ascenders.

The weight limit ("SWT 100kg") printed 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. A similar comment applies to heavier arborists.

The weight ("100kg") printed on the SHELL can easily be
less than the weight of a fully loaded caver.

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