"Wool Bolivia" was a common lining material listed in these ads, but I'm not sure exactly what specific type, or weave of wool that trade name refers to.
Many ads for this style show it worn for skiing. While ads for other jacket styles of the period show them worn in casual, or in work settings, ads for Laskin Lamb jackets show them almost exclusively as sports jackets. Photos showing these jackets actually being worn generally show them in other contexts.
Cuffs that flip up and button, so that as the young owner of the Laskin Lamb jacket grows, the jacket grows with him.
Chunky tweed and a knit cap.