I have a 3/4 PVC pipe and I need a fitting to put over it similar to this one.
They usually either have a small metal clip holding them in place you feel around it where it meets the ceiling and find a small metal thingie you push on. You will probably have to turn the alarm an inch one way or the other while pressing the metal thingie. Have a replacement 9v battery ready so you can put it right back up. Good luck.
FLOOR it and VAULT the speed bumps. Or just swing by your local shop and have them grease your suspension.
