Puzzler

And here is one that is actually really old, still makes me smile though.

What is this?

What? You need a clue?

Pffffff… ok then: We do not use them in tree care as we are in work positioning, not in fall arrest. There, now I have given it away.

Answers on a postcard, first correct answer wins… something. A t-shirt. If you get stuck, check back tomorrow for the solution.