This is my sketching stool. I got it for about $15 (costs like $19 now) from REI, and it's really really light, but very sturdy. I attached a camera-bag strap t it to carry it over my shoulder, it's a perfect and unobtrusive sketching companion. No longer must I sit on the dirty pavement. My only gripe is that I'm now quite high up and my paints are usually on the ground. But otherwise I love it.
If you're wondering, I wanted blue. They only had green in stock.
I’ve drawn this as an illustration to a new page on my site: Materials. Since I am so often asked what pens etc I use, I thought it would be nice to have a whole page showing what I use in my entire sketching experience, not just micron pens and cotman paints but my shoulder-bag and sketching stool. It’s not completely comprehensive however; I stopped short at revealing what I eat and what music I listen to while sketching.