Can I take the Perimeter Alarm on a camping trip if there is no electrical current available?
Yes. The Sentry Perimeter Alarm will work on battery power for about 5 hours. The unit may be placed on a picnic table to monitor a loved one. We suggest that the unit not be operated this way very often since the unit uses a total of 16 AAA batteries. • Do I need to Purchase a Mobile Locater separately? No. The Sentry Perimeter System includes the CTR 16 Mobile Locater. The Perimeter and the CTR 16 work together to form the invisible perimeter. With the combination of the two units, you have the ability to monitor an area AND have the ability to locate the wandered person up to a MILE away.