Hiking/Trekking Poles
If your hike requires stream crossings, trekking poles are great. Having two poles to anchor your way across a series of slippery rocks is invaluable. Even if I'm not using trekking poles on my hike, I'll usually carry them in my pack just for this reason. Similarly, if I need to test the depth of a stream or see how muddy the bottom is, trekking poles get the job done.