No Fly Zone® Frequently Asked Questions


What is WindRiver No Fly Zone®?
Exclusive to Mark’s, WindRiver No Fly Zone is a men’s and women’s apparel and accessory line that repels mosquitoes. Yes, such a thing exists.

Science and Technology

What makes No Fly Zone® clothing repel mosquitoes?
No Fly Zone products are treated with permethrin. If a mosquito approaches permethrin, it becomes disoriented and flies away.
What is permethrin?
Permethrin (pr·meh·thruhn) is a synthetic chrysanthemum, a chemical derived from a chrysanthemum flower. In other words, permethrin emulates a natural chemical that binds to fabric for long-lasting, odourless and effective protection against mosquitoes.
Will the No Fly Zone® treatment absorb into my skin?
Permethrin molecules have an extremely low absorption rate by human skin. Anyone concerned with chemical sensitivity should not wear No Fly Zone products.
What makes the No Fly Zone® technology different than other applications, such as DEET?
When a mosquito lands on DEET, it takes some of the DEET chemical away with it, transporting chemicals into the ecosystem. No Fly Zone garments have permethrin built into the fabric to prevent cross-contamination.
Will No Fly Zone® products keep mosquitoes away all the time?
We cannot claim No Fly Zone products to have a halo effect. Everyone, and their relationship to mosquitoes, is unique based on the carbon dioxide their body gives off. Mosquitoes may approach the fabric and fly away. If a mosquito does land on the treated fabric, the permethrin treatment should incapacitate it and prevent the mosquito from biting you.


Will No Fly Zone® lose its effectiveness when it gets wet?
No. We’ve anticipated the unpredictable weather conditions in Canada and encourage everyone to put our gear to the test. No Fly Zone garments remain effective for over 70 washings through a regular wash/dry cycle.
Is the product still effective if you wear a jacket overtop?
Yes, but the effectiveness will be limited if the jacket is untreated, limiting the benefits of the treated product. Thankfully, the full No Fly Zone line includes men’s and women’s shirts, shorts, pants, jackets and hats.
Why are the No Fly Zone® garments lined?
It is a Health Canada requirement for permethrin-treated clothing to be lined.
Do No Fly Zone® garments have UV protection?
Yes, but each garment provides a different level of protection based on colour and the UV application.
Are there plans to incorporate No Fly Zone® technology into industrial apparel?
Yes. We have approval to apply the technology to polyester and are working towards approval for cotton.

Children and Pets

Does Mark’s make No Fly Zone® for children?
No, we do not carry clothing for children.
Are pets at risk if they lick No Fly Zone® products?
Dogs are not at risk; however, cats may have a negative reaction to permethrin depending on the exposure level. To be cautious, we recommend you keep No Fly Zone garments away from your pets


I work for media and want to do a No Fly Zone® feature for my next story. Who should I contact?
We’re happy you asked. If you want to learn more about the No Fly Zone buzz (pun intended), please email us at: