Several months back I polled folks on the forum about various security alarm products that might be used in my H320. Few responses and most referred me to expensive hard-wired security systems. I opted to try the SecurityGuard III system from Desert Security Products. It is wireless. It has a built in motion sensor and alarm sounder. I added the additional wireless sensor, reed switches, external sounder, strobe and wireless key entry (and a few other unnamed surprises). The internal battery holds a charge for about 3 months; it isn't recommended that you leave it plugged in when you are gone. The installation took less than a couple of hours including options I purchased with it. After three months I am happy to report no false alarms and the system sounds every time I visit the boat assuming I don't cut it off first. I will say that the alarm is so loud that I don't recommend setting if off without ear plugs or for days your ears will feel like they they did after a Pink Floyd concert in the 70's. I do not sell the product and am simply reporting back to all sailors with a recommendation for a security solution that is less than $500 bucks and is very effective.