Jobst Vairox 30-40 mmHg Knee High Open Toe Compression Stockings with Zipper. Precise Fit. Durable. Gradient Compression. For indications requiring extra firm compression. Zippered Style. Unisex. Available in Beige. Fiber Content: 30-40 mmHg: 77% Nylon 23% Spandex. Care Instructions: Machine washable in lukewarm water. Tumble dry in low heat. Do not bleach dry clean or iron. Ships as a pair. Due to the nature of this item it is non returnable. 30-40 mmHg Very Firm Gradient Compression Indication Guide: Chronic venous insufficiency. Deep vein thrombosis. Post-thrombotic syndrome. Severe varicose veins. Severe edema / lymphedema. Venous ulcer. Lymphedema. Orthostatic hypotension. Postural hypotension. Helps Prevent DVT (Deep Vein Thrombosis).