With summer starting to kick in i am looking for ways to keep cool in the shed. Has anyone used some of the cooling vests available?

As far as i can tell there are evaporative types (Cooling Vests, Microfiber Performance Apparel, Headwear, and Animal Products by Silver Eagle Outfitters, Australia) and some where you insert gel packs to help keep you cool (COOL-OZ COOLING VEST (royal blue) - eBay Other Clothing, Clothing, Golf, Sport. (end time 28-Nov-09 23:13:45 AEDST)).

Are they any good, or a waste of time?

thanks
joez