Question 1

Could i keep these in my car during winter in case of an accident? Do they last a long time? When would i have to boil them?

Accepted Answer

Answers: Yes, they are safe to store in the car as long as they are not exposed to high heat or freezing conditions. They are water and may freeze. 
They last about 1 1/2 hours, give or take a little bit. Then they start to cool.
You have to boil them when they are fully crystallized and have cooled. Use care to not allow them to contact the sides of a boiling pot for too long.
I do want to address an answer someone else gave. They said that the warmers store heat. Not really true. They are a bag of water with dissolved salts. When the metal disc in the pouch is snapped, it initiates a chemical cascade creating a crystal made from those salts. In the process, heat is released. As long as they are liquid, they are cool. During crystallization, they release heat. Once the crystals are fully formed, they cool. Boiling them reversed the process and restores the liquids. I have on in my drawer that is over 20 years old and still works.

Question 2

sizes

Accepted Answer

Look further down on the Amazon page for product details, quote -"...This set includes 4 HotSnapZ round hand warmers (4" diameter) and 4 of our pocket sized HotSnapZ hand warmers. (3" x 5")" - I found the round ones are perfect for your gloves or jacket pockets (hands). The rectangular ones are great for you pant pockets (esp back pockets), as well as very excellent to pre-warm your boots the next morning (two per boot and stuff your socks in with them as well.) Only takes about five minutes in ideal outdoor temperatures to 'recharge.' THEY GET PRETTY DANG HOT WHEN ACTIVATED. Usable for about 30-40 minutes and then taper off gradually for another 15-20 minutes.

Question 3

Once activated how quickly do these take to get hot?

Accepted Answer

Almost instantly.  In a few seconds the start to warm up.  In less than a minute, they will be at full heat,. The warmth lasts for maybe 10 minutes.  At peak, it is VERY warm like holding a mug of really hot coffee but peak warmth only lasts maybe 3 minutes.  So compared with the kind of warmers that you shake, these have faster and warmer heat, but the heat does not last long.  Boil these and they are good as new.

Question 4

do they accidentally activate in your bag?

Accepted Answer

The more they are used, the easier the clicker is activated. At the right angle, if the heat pack is being stored in a purse or crowded bag, then yes it can activate. Not easily, but it happens

ASIN	B004CV2YXE
Battery Charge Time	10 minutes
Battery Description	rechargeable battery
Best Sellers Rank	#107,921 in Health ( See Top 100 in Health ) #486 in Heating Pads
Brand Name	Hotsnapz
Color	green,red
Customer Reviews	4.2 4.2 out of 5 stars (5,071)
Lower Temperature Rating	115 Degrees Fahrenheit
Manufacturer	Hotsnapz
Manufacturer Part Number	HWDuo-2418
Material Type	Acetate
Model Number	HWDuo-2418
Number of Items	8
Number of Packs	2
Power Source	Electricity
Recommended Uses For Product	Skiing, Camping, Fishing, Hunting, Snowboarding, Hiking, Cycling
Reusability	Reusable
Size	S
Target Use Body Part	Hand
Unit Count	8 Count
Upper Temperature Rating	130 Degrees Celsius

Hand Warmers - HotSnapZ Reusable Round & Pocket Warmers for Instant Heat

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