This version of the famous Howler fire alarm has a clever call point that does not require a replacement glass when used. You just insert the plastic key (supplied with new Howlers) and the plastic panel returns to its original position. This also stops the alarm. This model is IP65 rated for outdoor use with a 118db alarm and 9v battery (supplied) and is very popular for construction sites, temporary buildings, portacabins, small workshops, etc.