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RK Sicherheitstechnik Descender

Front View Rear View
Front View Rear View
Left Side View Right Side View
Left Side View Right Side View

Technical Details

I acquired my RK Sicherheitstechnik descender from Christopher Winslow in 2019.

My RK Sicherheitstechnik descender is 182 mm. tall, 123 mm. wide, 149 mm. thick, and weighs 1700 g. It is part of a kit that weighs 10.2 kg.

The kit contains the following items:

  1. Descender: The descender consists of a large die cast metal case containing an internal sheave attached to an external plastic control wheel by internal gears, a U-shaped clevis eye stamped from 1.6 mm. steel, and a cast steel hook. There are spring-loaded cams on the rear that face each other, providing a way to lock off.

    The descender has no permanent markings, but it has two stickers attached. The main sticker reads as follows:

    RK Sicherheitstechnik GbR Descender and Rescue Device
    Rope length m  Serialno: Yr of construction-▪▪
    Typ: AG 10 □  AG 10 S□  AG 10 T□  AG 10 Hub A □  AG 10 Hub B □  AG 10 Hub C □  AG 10 K Hub A ▣
        AG 10 K □  AG 10 KS □  AG 10 KT □  AG 10 Hub K □  AG 10 Hub E □  AG 10 K Hub K □
    pREN341:2008 Kl. 1A  EN1496:2007 Kl. B fulfills technical ANSI/ASSE Z359.4-2007 3.2.7 and 3.2.8
    max. abseiling load:    100kg/30kg     max abseiling height    400 m/200 m
    in rescue situation max abseiling load 225 kg max. abseiling height 100m / 125 m (EN341:1992)

    The first rectangles on the second line has "78" stamped inside, the second has "A" printed and "31117" stamped inside, and the third has 2011" stamped inside. The square dots represent punch marks through the sticker.

    The other sticker is less painful: it merely states that the next inspection is due in 3/12.

  2. Rope: My descender came pre-rigged on 78 m. of 9 mm kernmantle rope. Each end of the rope has a sewn eye with a plastic liner. The stitching is covered with thick clear heat-shrink with a tag underneath. The tag is printed with "PSA," "Yr of manf. 03-2011." "length: 78 m," "EN 1891 A, and "KM-ropeØ 9mm."

  3. Rigging hooksTwo rigging hooks: These hooks are 325 mm tall, 150 mm wide, and are made from 12 mm. diameter plated steel. They feature a typical industrial double latch. One side of each hook is stamped with "H-017 2010 (224563)," "CE0321 EN362:2004A," "↔ 23 kN," a book-with-an-"i" icon, a CSA logo, and "Z259.12."
  4. SlingsSlings: The kit includes two 1.8 m slings sewn from 25 mm. webbing.
  5. Edge protector and Al carabiner Edge protector and Al carabinerEdge protector: The edge protector is cast aluminum. It is 113 mm. tall and long and 80 mm. wide, with a 24 mm. rope slot. It has about 1 m. of very soft 6 mm. cord attached.
  6. Steel carabinerTwo carabiners: One steel self-locking and one aluminum screw gate.
  7. Edge protector and Al carabinerCarry bag: The carry bag is waterproof coated fabric with backpack straps, a fastex-style buckle closure, and a clear document pocket with a zipper closure. The bag is 700 mm. tall and 300 mm diameter.


The RK Sicherheitstechnik descender is designed for professional windmill rope access technicians. CLimbers and caves would find it too heavy for their needs, and cavers would also worry about how it might perform in mud.

The sheave turns freely but the internal gearing drives the external wheel at the same time, providing some additional friction. Most of the friction seems to come where the rope enters the body at the top. This edge is too sharp for me.

The markings on the sticker are rather confusing. What is the safe maximum weight: 100 kg, 30 kg, or 225 kg? I'll assume 30 kg. is a minimum, not a maximum, but why is it safe to load 225 kg. during a rescue when 101 kg normally exceeds the safe working limit. How does it know? OK, let’s assume that 100 kg. is safe up to 400 m. but 225 kg is only safe for 100 m. Wait a minute, the rope is only 78 m. long. I confess to being a bit facetious, but I can see how some people might get the wrong idea.