JOSEF SEIBEL Jasper 50. A men's Chelsea boot crafted using high-quality leathers and a Top Dry-Tex membrane. The Jasper 50 Chelsea ankle boot has a unique brogue style leather overlay detail on the heel and contrasting elasticated side gussets - creating an all-year-round smart casual waterproof boot. Sitting atop a flexible, hard-wearing, and lightweight sole with a soft textile lining and a cushioned, removable footbed.