Merrell Siren 4 Thermo Mid Zip Wp

With 25 years of experience in women's specific fit from Merrell, the Siren 4 Thermo has been designed to fit the unique contours of the female foot and provide comfort, support, and stability even on long hikes. 200 grams of extra insulation provide warmth and protection. Thanks to the new SOLARCORE® insulation, a lightweight insulation material originally developed for NASA, you no longer have to worry about warmth.

The all-new medial zip makes it easy to put on and take off, a new improvement resulting directly from customer feedback. Merrell waterproofing on the upper keeps your feet dry. With Vibram® IceTrek® underfoot, traction is maintained even in the wettest and slipperiest conditions. For the first time with Vibram® traction lugs for more grip on uneven terrain.

• Waterproof membrane that seals out water and allows moisture to escape.
• Upper made of waterproof full-grain leather and knitted fabric.
• 100% recycled laces and webbing.
• Durable, waterproof, medial YKK zip for easy on and off.
• Bellows tongue prevents dirt penetration.
• Protective and abrasion resistant rubber heel and toe cap.
• 100% recycled fleece lining.
• 200 gram synthetic Primaloft® Gold Eco Series insulation.
• SOLARCORE® Aerogel insole provides superior underfoot warmth while being extremely flexible and ultra-thin.
• 100% recycled mesh footbed cover.
• Cleansport NXT treated for natural odour control.
• 5% recycled PU removable footbed.
• FloatPro foam midsole for lightweight and durable comfort.
• Vibram® Icetrek outsole for improved grip on very cold, icy, or snowy surfaces.
• Vibram® traction lugs specially designed to increase traction and repel debris with every step.
• Pile height: 28.5-20.5 mm.
• Counterbore: 8 mm.
• Cleats: 5 mm.