I've been poking around online, looking for a "travel"
strop. I came across this item on KnifeCenter.com:

High quality strop for sharpening and honing. Made out of smooth Russian leather, and has a slate plate on the back side for perfect resharpening of straight razors. Two long cavities below the leather provide the necessary flexibility for an effective and gentle honing of the thin razors. Dimensions (leather strop/slate): 1-5/8" x 15-3/4" x 1-1/4". Total approximate length: 13". Includes a traditional push-cover and instruction manual. Made in Solingen, Germany.

Is anyone familiar with this product?
What sort of stone is the "slate"?

Thanks in advance for your comments.

Paul