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Kong Back-Up
(#1716, 2650)


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 Back-Up from On Rope 1 in 2010. I acquired another in 2017 as part of Bob Thrun’s collection.

My Kong Back-Up is 95 mm. long, 65 mm. wide, 26 mm. high, and weighs 209 g.

The Back-Up consists of two irregular 3 mm. aluminum plates enclosing an actuating lever, a mode select lever, a transfer lever, and a rope anvil.

Each plate has an arcuate cutouts at the right side of the device. The eye of the actuating lever sits between these cutouts, where it is protected by a stamped lip in the rear plate. This end of the lever has a 14.1 mm. attachment eye, while the other end has a U-shaped projection that rides against the rope.

A 6 mm. stainless steel axle on the left side supports the transfer lever. The axle passes from front to back, passing in sequence through the front side plate (free to rotate), a cast stainless steel transfer lever, the mode select lever, the rear plate (fixed), and a steel washer. The actuating lever is weakly spring-loaded counter-clockwise, forcing the bottom toward the anvil.

The mode select lever pivots on the actuating lever axle. The left end has a spring-loaded pin that rides in a curved slot in the rear plate. Larger holes at the end of the slot allow the pin to catch, holding the mode select lever in post ion. In the upper hole, the actuating lever rides parallel to the rope, while with the pin in the lower hole the actuating lever is free to close fully.

The anvil is cast stainless steel. It is riveted to the rear plate. A pin on the anvil extends into a hole on the rear plate, preventing anvil rotation.

The front of the Back-Up is printed with the Kong logo, "ITALY, "BACK-UP," a rigging illustration, A man with an "X" across his chest, and two men with an "X" across them. The rear is printed wit "CE0426," "EN 353-2:02," "EN 358:99," EN:12841 A/B:06 - 100 kg," a right brace ("}") aligned with the preceding three pointing to a circle-with-a-dot-inside followed by "ø 10-11-12," a book-with-an-"i" icon, "100981 10 0715," the UIAA logo, "EN 567:97, a right brace ("}"), a circle-with-a-dot-inside followed by "ø 10-11-12" (again), and a circle followed by "ø 12." The rear plate is stamped "↑↓" near the upper end of the mode select pin slot, and "↓" with an "X" through it near the lower end.


The Kong Back-Up adds an interesting feature to devices like the heightec-PMI Vector rope grab and Ural Alp Basic ascender; specifically, the actuating lever. Under load, the actuating lever forces the rope against the upper portion of the transfer lever, pivoting the transfer lever and forcing the lower portion to squeeze the rope against the anvil. This works with either position of the mode select lever.

When the mode select lever is in the upper position, the Back-Up slides more freely on the rope.

The SOB Grab is essentially the same device.

Tests reported by the the US Bureau of Reclamation
showed that the Back-Up does not always engage
It sometimes allows the user to drop the full length of the safety rope.

(Shaun Reed, "Drop Testing of Rope Access Backup Devices," also see

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