Like Fireglider and texaswiz, I added the radio shack siren to my HD security system. Cost about 6 bucks and took about 10 minutes to install.

 

We have HD alarms with sirens and pagers on both of our bikes. My wife often takes hers to work and parks it at the rear entrance which is probably about 800 ft or so from her office. On one occasion, the pager went off and she excused herself from a meeting to run to her bike and found a clown sitting on it and showing off in front of some friends by pretending to drive it. She only received the prealert as he hadn't set it upright at that point to initiate a full alarm. I was amazed that it actually had worked that far away in a metal building. For a lot greater range, I am going to modify the antenna type and location as I have seen on another site, which is an especially great addition with the batwing as the long range antenna can be mounted inside . Range reported is 3 to 4 miles vs the 1/2 mile I get now.