Heartbeat sensor
This is one of the most important pieces of equipment available to Rainbow team members. This device, when used as your active item, will track the heartbeats of all nearby humans, indicating the locations of all terrorists and hostages. It's often a good idea to equip each team leader and one or two other troopers with one of these. If your leader is the only one carrying one, you can't use the device if he goes down.

Demolitions kit
This is used to help disarm explosive devices and can be used by any type of team member. Though you'll most often want to assign it to a demolitions expert, nonexperts will often find it more useful, as the kit can significantly speed up the disarming process.

Lockpicking kit
This kit is used to - you guessed it - pick locks. This can come in handy when breaching locked doors, as some team members take quite a long time to manually pick a lock.

Electronics kit
This tool is useful for working with any special electronics systems; alarm systems and surveillance systems are two good examples.

Door charges
This explosive rig is used to blow open doors. They should not be used on missions that require stealth, but they are effective at stunning, wounding, and even killing anyone standing near the door when the charge goes off (so just make sure there aren't any hostages nearby when you use this little toy). Door charges are handy, but you can get through every Rainbow mission without using them.

Flashbangs
Here's a fun little toy. Flashbangs do exactly that: they go bang with a big, disorienting flash. Typically, you would throw one of these into a room before entering (while staying out of sight, of course). The ensuing explosion will not seriously harm anyone inside the room, but it will stun everyone nearby, giving you an extra few seconds to enter the room and take down the bad guys. Consider this an essential tool of the trade and try to take some along on each mission.

Next: More Equipment and Miscellaneous Accouterment