A bug out bag is a bag prepared with enough supplies to last you for a minimum of 3 days.  It’s recommended to have one bug out bag per person.   Ideally, a completed bug out bag should be stored near an exit of your home.  This way, in an emergency, the process of gathering important items has already been taken care of letting you use the precious minutes you have remaining for other things such as pets or assisting other people, other non-bug out-bag important items, or just having a head start on fleeing.

Ideally, a bug out bag should carry items that cover all the survival categories (Communication, Energy, Fire, Warmth, Food, Health, Light, Safety, Shelter, Water, Entertainment, and Accessories) with preferably some items doubling up on important categories such as fire.

What separates a bug out bag from a car kit or a personal survival kit is its size and weight.   You don’t have the same space availability as a car kit, but you are also not expected to carry it as often as a personal kit so your weight, load and item size will fit somewhere between the other two kits (car and personal).
A bug out bag should contain all the items that your personal survival kit does plus more.   Unlike the personal kit, you should be able to afford the space to have 3 days worth of food and drinking water, but those alone may not be sufficient.  Better items for creating fire, shelter, and communication will increase your chances of success and your options for health and accessories will widen greatly because of the extra space in your bug out bag that you wouldn’t ordinarily have in a personal kit

So, aside from the bag or receptacle to hold your survival items, here are items suggested for the kit:
For communication:
XL Sight-Grid Signal Mirror – replace
2-In-1 Flint Fire Starter and Survival Whistles
World Famous Multifunction Survival Whistles
World Famous All-Weather Notebooks
Enola Gaye Wire Pull Smoke Grenades

For energy:
Xtreme Power Stick Portable Cell Phone Battery Chargers
Xtreme Power Stick Portable Cell Phone Battery Chargers
Bulk Duracell AA Batteries

For warmth:
Compact Mylar Emergency Blanket
North 49 Base Camp Extreme Cold Winter Sleeping Bags – replace
Coghlan’s Reusable Thermal Space Blankets

For food: Need to replace with freeze dried food pouches

For health:
Coghlan’s Trek I First Aid Kits
Coghlan’s Emergency Preparedness Kits
Coghlan’s Biodegradable Camp Soap
Coghlan’s Snake Bite Kits
Coghlan’s Foot Care Kits

For light:
12-Hour Emergency Light Sticks
Camping Lanterns – Small Square Stainless Steel
IIT Swivel Panel LED Camping Lanterns – Replace
Coghlan’s 36 Hour Survival Candles

For safety:
Tru Flare Bearbanger Signal Cartridges
Tru Flare Pen Type Flare and Bear Banger Launcher Kits
Model O2C TruFlare Pen-Type Launcher
Bear Bells
3-in-1 Emergency Car Survival Tool

For shelter:
Coghlan’s Emergency Survival Ponchos

For water:
LifeStraw Go Portable Water Filter Bottles (lets you refill repeatedly vs. carrying around several bottles of water)
Aquatabs Water Purification Tablets
World Famous 14 Litre Expandable Water Carriers

For entertainment:
For accessories:
Coghlan’s Camper’s Knife, fork and Spoon Sets
Bell Outdoors GHH-FU3 Woodsmans Edge Field Utility Knife Combo
Coghlan’s 12-in-1 Scissors
World Famous Glow-In-The-Dark Compasses
Coghlan’s Store-N-Pour Contain-all Container Sets
Stainless Steel 10-in-1 Multipurpose Pocket Survival Tools
Grizzly Outdoors Canteen and Cup Kits
11-Inch Hunting Knives with Fire Starter