Home Alarm System DIY 100% Wireless Entry Sensors protect vulnerable doors & windows. Sensors have a 400ft range of communications (so if your home fits inside of a football field, SimpliSafe has you covered). Insanely easy to self-install, plug-n-play solution. No wires, no hassle. Get 24/7 Peace of Mind with SimpliSafes 24/7 Alarm Monitoringno contracts, no commitments, cancel anytimejust $14.99/month. Cellular, GSM, No Phone Line needed: All SimpliSafe systems come with built-in cellular technology so your alarm will reach our monitoring center without the need of a phone line. 100% Satisfaction Guarantee: If you dont love your SimpliSafe system, call us within 60 Days for a full refund, well even pay for return shipping.