Prime Workboot - Covered CoiL Rugged Outsole | Pain Relief Footwear

Z-CoiL Footwear is designed to provide superior comfort, pain relief, and performance. Use this guide to find the perfect size and fit for your needs.

General Sizing Information

Z-CoiL shoes run true to size. Every pair includes a 3mm insert to help adjust for half sizes.

Women's Sizes

Size	EUR	CM
W5	35.5	21.5
W6	36.5	22.5
W7	38.0	23.5
W8	39.5	24.5
W9	40.5	25.5
W10	42.0	26.5
W11	43.0	27.5

Men's Sizes

Size	EUR	CM
M8	41.0	26.0
M9	42.5	27.0
M10	44.0	28.0
M11	45.0	29.0
M12	46.0	30.0
M13	47.5	31.0
M14	48.5	32.0

Unisex Size Conversions

Most Z-CoiL styles are unisex. Use this chart to convert between men’s and women’s sizes:

Women’s to Men’s Conversion:

Women's Size	Men's Equivalent
W4.5–5.0	M3.0–3.5
W5.5–6.0	M4.0–4.5
W6.5–7.0	M5.0–5.5
W7.5–8.0	M6.0–6.5
W8.5–9.0	M7.0–7.5
W9.5–10.0	M8.0–8.5
W10.5–11.0	M9.0–9.5

Men’s to Women’s Conversion:

Men's Size	Women's Equivalent
M7.5–8.0	W9.0–9.5
M8.5–9.0	W10.0–10.5
M9.5–10	W11.0–11.5
M10.5–11	W12.0–12.5
M11.5–12	W13.0–13.5
M12.5–13	W14.0–14.5
M13.5–14	W15.0–15.5
M14.5–15	W16.0–16.5

Half Size Adjustment Instructions

Z-CoiL doesn’t manufacture half sizes, but every pair includes a 3mm insert to fine-tune the exact half size fit. Follow these steps:

1. Remove the Insole: Take out the Z-CoiL insole from the shoe.

2. Insert the 3mm Half-Size Insert: Place the insert inside the shoe where the insole was.

3. Reinsert the Insole: Put the insole back on top of the insert.

This method fills in the space of a half size, ensuring a snug, comfortable fit.

Spring Strength Guide

Z-CoiL shoes come with four different spring strengths, predetermined by shoe size. While most customers find the factory settings ideal, some may need adjustments based on their weight or walking/running style.

Spring Strength Recommendations:

Spring Type	Recommended For
Small Spring	Women’s sizes 5–7 (up to 150 lbs)
Medium Spring	Women’s sizes 8–11, Men’s 8–9 (120–200 lbs)
Large Spring	Men’s sizes 10–13 (160–240 lbs)
XL Spring	Men’s size 14+ (220 lbs+)

Tip: Aim to compress the spring about 75% during normal walking. If you "bottom out" (fully compress the spring), consider a stronger spring. If the shoe feels too stiff, you may prefer a softer coil.

Requesting a Stiffer Coil: If you prefer a softer or stiffer coil, please add a note to your order at checkout. We will gladly exchange the coil to suit your needs better.

Width Options

All Z-CoiL shoes are designed with a wider toe box to reduce irritation in the toes and ball of the foot.

Width Descriptions:

D Width (Wide): Available in the Freedom, Legend (all), Olivia, Sofia, Toffler, and styles.
E Width (Extra Wide): Available in the Outback, Prime, and Sidewinder styles.

Choose the width that provides the most comfort and accommodates your foot shape.

Additional Information

If you have specific needs, such as adjusting for over-pronation or requiring a custom fit, please contact our customer service at 800.268.6239 or email painfree@zcoil.com