A lap blanket and a bed blanket don't need to be the same size. The Arcturus Rainier Wool Blankets gives you a useful choice between a smaller Throw and a longer Twin, with listed weights that make the storage tradeoff easy to see.

I'd pick the intended use first. A larger blanket can sound like better value while being less convenient for the chair or vehicle seat where you'll actually keep it.

Two Sizes to Compare

Throw: 50 by 60 inches, approximately 2.5 pounds.
Twin: 64 by 88 inches, approximately 4.5 pounds.
Outdoor wool-blanket product line.

The Throw may be the easier size to manage across your knees. The Twin provides more coverage, but its extra material is something you'll carry and store even for a short evening outside.

Lay It Out at Home

Use an existing blanket to mark out the listed dimensions. See how much remains around the feet or shoulders, depending on the position you want. That gives the numbers a practical meaning before you choose a size.

If you're buying it for a vehicle, try the folded space too. A blanket you can reach quickly is often more useful than a larger one buried under everything else.

My Take on the Range

I'd compare the Rainier for ordinary outdoor sitting and extra bedding, with the size chosen deliberately. Confirm the full material composition and care instructions for the selected version rather than assuming every wool product washes the same way.

For planned sleeping, consider the whole bedding arrangement and weather separately. There isn't a verified temperature rating in the product description used here. The appeal here is choosing a familiar blanket size with an explicit weight, so the purchase fits a real place and a real use rather than a vague bigger-is-better idea.