FIR Technology
Ursuit’s Deep Heat system employs Far Infra Red rays, the same electromagnetic radiation as found in our normal surroundings with radio waves, microwaves, X-rays and sunlight.
FIR radiation penetrates the human body to a depth of around 50mm, exciting our molecules and thereby warming the blood and tissues.
At first glance this looked scary. Would it boil my blood; was I going to suffer any long-term damage to my vital organs; more importantly, was I going to glow in the dark?
Following exhaustive research (a Google search) I found that FIR is widely used in healthcare, one of its advantages being that it promotes the growth of white blood cells, which in turn boost our natural immune system. So the heating system is apparently safe and natural.

The Design
The vest resembles a waistcoat and is made from a stretchy polyamide elastane mix with a polyester fleece lining.
It has three FIR pad pockets – two at the chest either side of the front zipper and a larger single pocket across the middle of the back.
A further two pockets at the front of the hips take the rechargeable 8.4V li-ion battery. This powers the exothermic heating elements and has an O-ring sealed screw-down connector. The elements and connecting wires are removable from the vest so that it can be washed.
The controls are accessed via a single rubberised button on the battery-pack that acts as an on-off switch, with a set sequence of pushes to scroll through the three heat settings – high 60°, medium 50° and low 40°C – and to lock or unlock the system. The battery compartment vibrates for a second to confirm that the settings have changed.
Burntimes (pun intended) are substantial.

On full heat the battery lasted for around 360 minutes, giving plenty of time to pre-heat the body and to stay warm when the dives are over and wind-chill becomes a potential problem.
The FIR thermal modules are sealed in heat-welded PVC covers to keep the whole system waterproof.

In Use
I visited New York City at the end of February. Temperatures had plummeted to levels not felt since the 1930s, and the Hudson River between Manhattan and New Jersey was solid with ice floes. Real-feel air temperatures fell to around -17°C, and clear skies meant that it was even colder at night.
I wore the Ursuit vest under my jacket and over a long-sleeved T-shirt. The pads heated quickly, warming my skin initially, and about five minutes later I felt the invigorating effect as the infra-red heat penetrated my body.
Warm blood means warm hands, feet and head, and all my extremities felt toasty. The Arctic conditions paled into insignificance.
One of the things to do in the Big Apple is to visit the top of the Empire State Building. This wasn’t as straightforward as I had expected, because with security rightly a priority I had to explain why I was wearing a vest with wires in it while trying to access one of the world’s most iconic buildings.
Thankfully the security staff had seen this type of heated garment before and allowed me up to the top while still wearing it. They did however confiscate my camera tripod.
Back on home soil I took the vest to my local inland dive-site at Wraysbury. I intended to put it through its paces under water but unfortunately discovered a leak in my drysuit.
However, Wraysbury’s owner Richard Major had been using the Ursuit system throughout the winter and was adamant that without it he wouldn’t have been in the water as much as he had. “It’s made the difference between an hour’s dive in water that’s been as low as 4°C or bottling out with a stay in the warm clubhouse,” he said.
The fact that the FIR penetrates the body means that the user’s core temperature remains stable. This in turn keeps the blood flowing to the extremities, so your hands, feet and head stay warm, a real advantage over heating elements that just warm the surface areas of
the skin.

Conclusion
This FIR technology isn’t as scary as I first thought; in fact it’s as natural as sunlight warming the body, with the added advantage
of no ultra-violet rays to burn the skin. The Ursuit FIR Deep Heat System vest isn’t a unique concept in the dive-kit world, but offers a great solution to the challenges of coldwater diving.
It certainly works for icy land-based activities, and according to the guys at Wraysbury it has worked wonderfully under water throughout the freezing winter months, making the vital difference between calling a dive off or actually taking the plunge.

PRICE £300
SIZES M, L, XL
POWER LEVELS High-60°C, Med-50°C, Low-40°C
BURNTIMES High 3hr, Low 5hr
POWER 8.4V li-ion rechargeable battery
CHARGER 110-240V mains
CONTACT www.liquidsports.co.uk
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