Z-CoiL Pain Relief Footwear Men's Prime Black Boots Half sizes not available, order next size up. Example W8.5 should order a W9.0. A special  size insert is provided for comfortable fit. Built-in rigid Z-Orthotic to protect and support plantar ligaments, reducing the pain of plantar faciitis, heel spurs, and arthritis. Patented conical heel spring - the Z-CoiL - to reduce up to 50% of impact as it eases overall fatigue and back pain. 3/4" forefront cushioning shields delicate toe joints, ligaments and tendons, while a wide toe box relieves joint pain and pressure. Forefront flex line and a rocker bottom sole to aid a fluid, natural walking motion. Rubber sole for additional slip resistance.