Derwent Pencil Extender
When sketching, I like to use black color pencils (Blick brand, specifically), to help nail down gestural sketches without getting finicky. Since I sketch a lot, I tend to tear through pencils pretty quickly, and I started looking at pencil extenders hoping to be able to utilize the remaining pencil nubbins. While I've tried a few brands, I've found that most can't get tight enough to hold the pencil in place, causing it to slip and slide while I'm trying to draw.
During my search for the perfect pencil extender, I came across Derwent's Pencil Extenders. Available in packs of two with two different sizes, the black extender, which is intended to hold pencils up to 7mm in diameter, is a perfect fit. Lightweight yet sturdy, both sizes of Derwent Pencil Extenders have a screw fitting that doubles as a pencil grip, and if you sketch too vigorously (or hold your pencil too tightly like I do), this may bite into your hand a bit.
Although my silver Derwent Pencil Extender, which is sized for 8mm pencils, never sees any use, I use my black extender on a daily basis, and the rubberized matte black body shows little wear. A constant companion in my pencil case, this extender is an affordable option that extends the life of your favorite drawing pencils.