I've reviewed several Derwent pencil cases and pouches already. Here's another one, the Derwent Traveller Pencil Pouch.
It's a pencil pouch with an elastic band that you can attach to your hardcover sketchbook cover. It works well for vertical A5-A4 sketchbooks.
On the front of the pouch is a small pocket. That pocket with the elastic band above can hold around 6 pencils. There's a bigger pocket behind that can hold another 6. So in total, the pouch can fit around 12 pencils.
I'll be careful of the button on the back that can damage your pencil lead if your pencil is too long and the lead is in contact.
The elastic band actually has holes along the length. You can detach the band from the button and use other holes to adjust the length of the strap to fit the height of the sketchbook. At maximum length, it can fit an A4 hardcover.
Of course, it's good for pens as well.
It's quite affordable and I think it's quite value for money.
However, for cases or pouches that attach to sketchbooks, my preference will still be the Accurasee Sketch Caddie.