The wooden layer used with the SpiderJack brake-levers are made from pock wood, an especially hard and heavy wood. Most of the precious pock wood comes from Central America, traded only under strict legal control. Its botanical name is Guajacum officinale L. Depending on its origins it carries additional names like "coulteri" (Mexico) or "officinale" (Antilles).

In Europe the name "pock wood" derives from the times, when its resin was used in the fight against pox. Because of its high proportion of oil combined with great density pock wood is a well known natural product and very abrasion resistant. Even the drive shafts of steam ships were ounted on pock wood.

As is well known wood makes a poor conductor of heat which is even more valid with pock wood. So it doesn't come as much of a surprise when controlling a rope by the SpiderJack's pock wood break conducts only very little heat.