Descending Device Considerations

There are many things to consider and compare. It will come down to that balancing act of easy to use, being light and durable, simple to tie off, cost effective and multi-functional, along with what you can live without.
I hope this will help in some way.

Cost
With today’s economic awareness making an educated purchase is of greater importance. As our finances are held in closer scrutiny, finding the right device for you is of more importance. With so many devices on the market making that choice can be a daunting task. So within this document you will find considerations, comparisons, and some cautions. Remember to always research, read the manufactures instructions, and practice with the device safely (with a belay) before taking it underground.

Weight
Every gram does count. The saying “light is right” comes to mind. Not necessarily true, however it is defiantly a large point of consideration among devices that suit the needs you require. If you are going to remote places and will be carrying it, weight will be a higher priority than someone operating locally. Each gram equals more calories used.
*The Italain hitch is just the weight of the carabiner, 0 grams for a device.

Replaceable Parts
Can the user in the field replace worn or damaged parts? With all the muddy, dirty ropes, the descenders will undergo a lot of damage, and wear. This could spell an early end of an expedition. You may be in a remote place, and have to maintain/fix your equipment yourself. So does the manufacturer permit this? And can it easily be done?

Rope Diameter
Does the device function well and/or is rated to be used with various rope diameters?

Load limit
Is it rated for one or two person loads?
Is there still smooth operation if the load/operator is light weight?
* Some devices can be used in emergencies for 2 person loads.

Friction Adjustment
Does the device incorporate a way to easily adjust the friction during use?
Long descents will require a descender that can vary its friction with ease.
* Do not forget about using an breaking carabiner to add friction.

Conditional self belay
Is a conditional self belay incorporated in the device?
* it is suggested that you use a form of belay, whether from the device or created by the operator.

Length
Size does matter! During SRT change-over, the longer the descender the more difficult change over can be, along with some tie offs. Also with limited space a longer descender may not be as functional. Finally, length equals potential weight.

Durability
What it is made out of matters as well.
Aluminum is a softer metal that offers more friction than steel. Aluminum will wear faster than steel. Steel being more durable is heavier and “faster” than aluminum.
Titanium has been around for a while and is one of the lightest, but also is the most expensive, because of its limited use in descenders I have left it out.
Each type of metal has its own heat dissipation properties as well, a consideration on long descents or lowers.
Consult the manufactures recommendations as to how much wear is safe for the operation of the chosen descender..

Other Points of Consideration

The environment of use, icy or muddy ropes? Local or remote areas of use?
Does it need to be orientated in a certain direction to work?
Can it be used for Multi purposes, like ascending rope, or within a haul system?
Can it be used as a belay device (lead and second/top)?
Can slack be easily removed from the system?
Is it easily tied-off and is the tie-off secure and compact?
How many rope strands can it operate on?

Speed and simplicity are key factors as well.
It goes without saying the more you use something the quicker you will become at it. That will only take you so far, if it has 25 steps vs 4 steps the latter will in the end be faster and safer (less to double check and less to forget).
Can the device be operated with one or two hands?
Last of all, will your descender twist, kink or otherwise damage the rope?

Summary
Know your device, practice with it in a safe environment before using it in the field and read the manufactures instructions!
Personally start with Petzl's Simple, it is the best device to learn on, and once you have become proficient at SRT, if you wish, then move to Petzl's Stop or the Brake Rack. Not the other way around.

The Meat and Potatoes

 

Cost

Weight

Field Replaceable Parts

Rope Diameter

Friction Adjustment

Conditional Self Belay

Recommended for Caving

Climbing Belay Tube Devices (Various)

$18-68

55-158g

No

7.5-11.0mm

No

No

No

Petzl Id (Rig, S, or L)

$180-220

380-530g

No

10.5-13.0mm

No

Yes

No

Figure 8’s (Petzl, DMM, SMC, Black Diamond)

$14-40

82-213g

No

8.0-13.0mm

No

No

No

Semi-Auto Locking Belay Devices (Cinch, Gri Gri)

$70-97

182-225g

No

8.0-11.0mm

No

Yes

No

Brake Racks (BMS, SMC, Petzl)

$90-120

470-828g

Yes

8.0-13.0mm

Yes

No

Yes

Spool Descenders (Stop, Simple, Anthron, Kong)

$63-170

240-340g

Yes

8.0-12.0mm

No

Yes to some

Yes

Scarab (Titanium and Steel)

$100-250

185-385g

No

6.0-13.0mm

Yes

No

Yes

  •  All prices are “ball park” figures from 2011.
  •  Not all of the devices operate with the complete range of rope diameter of its grouping.
  •  The numbers given are a range in which the grouped descenders are rated to.