Three different phase change packs are available for Polar’s Cool58 zipper vests and we tested the two lightest (the heaviest would put the vest close to 8 lbs, too heavy for most Msers). The 400g cooling packs (pictured at right and in the top row below) are a set of 8 phase change squares that cool to a reported 58°F. These lasted a reliable 3 hours in room temperature conditions, while the 500g cooling packs (four larger connected tubes) lasted over 4 hours, easily among the best performers of the entire test. We like each style of cooling pack for separate reason.
The vest is the same basic design as their popular Kool Max vest, and it is fairly easy to adjust and customize the fit. Getting the right fit at first can be awkward and may require a bit of trial and error, but that’s a one-time deal. We found the 400g packs more comfortable overall, especially when seated as the packs are flatter. For women, the smaller packs fit the chest better as well. However, as the packs “thawed,” the smaller ones had a tendency to slide down and may bunch slightly, unlike the 500g packs, which stayed in position more reliably. Since phase change packs can be recharged quickly in ice water, these vests are easily portable. This vest and the Glacier Tek vest are tops in endurance and make reliable options for over-clothes cooling. Note: scores specific to the 400g cooling packs are in parentheses.
Endurance: 5 (4)
Comfort: 3 (4)
Concealability: 1 (2)
Sports: 2 (3)
Cold Sensitivity: 4
Weight: 5 lbs 6 oz (4lbs 6 oz)
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