Falke No. 4 Pure Silk Gentlemen Knee High Sock (15661). The Falke No. 4 Pure Silk Gentlemen Knee High Sock 15661 gives you comfort and sophistication, with a sleek, tall leg, hand-linked toes and durable construction. Falke's No. 4 Pure Silk Gentlemen Knee High Sock is made from finest Chinese mulberry silk blended with polyamide.