The world of personal heating products has come a long way from the days of the hot pad and the hot water bottle. Advances in technology have made it possible to access heat virtually anywhere during nearly any activity. One of the most popular advances in personal heating technology is the hand warmer. The objective of the hand warmer is to provide on-the-go access to heat for hands, feet, or other sensitive areas.

It can be difficult to choose a hand warmer, but consumers should bear in mind the circumstances in which they will be using their hand warmers. An individual who is out on a long hike, for example, may benefit best from chemical hand warmers. Chemical hand warmers are often disposable, and heat is created from one or more chemical reactions between ingredients contained within them.

Another viable option for those on the go are hand warmers that are powered by lighter fluid or liquefied petroleum gas (LPG). These models are refillable and provide hours of heat to cold body parts. Most folks who opt for this model of hand warmer do so because of environmental concerns; a reusable hand warmer creates less waste than its disposable counterpart.

One of the more high-tech options available are hand warmers that connect to a computer via a USB slot. USB hand warmers come in a couple of different forms, the most popular two being mitten-shaped hand warmers and a hand warmer that is merely a heated cylinder that the user can grasp for instant warmth. Both forms work by converting energy output from the USB slot to give a slight jolt of warmth to chilly fingers.

A readily available no-frills option is the battery-operated hand warmer. Battery-operated hand warmers utilize disposable or rechargeable batteries. Disposable battery-powered hand warmers are usually less costly, but produce more waste. Rechargeable hand warmers work much like a cell phone--just plug it in and wait for it to charge.

It should be noted that improper use of hand warmers may cause serious burns or other injuries. Hand warmers should not be left unattended at any point. It is important to always consult the manufacturer's safety instructions prior to using any of the products. Consult a medical professional if accidental injury occurs.