This is a piece of
climbing apparatus that allows you to ascend a rope. It is the lightest ascender on the market
weighing in at 22 grams. It is produced by
Petzel.
The triblock is a long u shaped piece of metal which
sits around the rope. There are holes in the sides through
which a carabiner can be clipped. As you pull down
on the carabiner the carabiner and the triblock
squeeze the rope between them gaining purchase on the rope.