A640 Steel Toe Polyurethane in Color Black | BIRKENSTOCK US。Birkenstock A 640 professional clogs offer exceptional protection and comfort for demanding work environments. Constructed from durable, grease-resistant polyurethane, these closed-back clogs feature a steel toe cap for enhanced safety. The replaceable anatomically shaped cork-latex footbed provides signature support, while the non-slip, oil- and grease-resistant profile sole ensures stability on various surfaces. Designed for hygiene and longevity, the entire shoe (excluding the footbed) is washable up to 80° Celsius.