I was just shopping for some replacement dust mask filters and stumbled across these wearable cooling devices. Some work with evaporation and probably not as effective as something with cold packs due to our high humidity. This company has a design that has rechargeable cold packs which are supposed to last 2.5 hrs. https://www.glaciertek.com/about-our-cooling-technology/ If you are using them, do they make it comfortable working when it's hot in the shop? Do they get in the way?