SIREN DISC ALUMINIUM 175mm DIA C/W 10/6mm STEM
The 'Siren Disc' consists of a metal disc about 180mmD, mounted on a central shaft so that it can be rotated. The disc has 4 rows of holes around it and when a fine jet of air is blown through the rotating holes, a 'siren tone' is produced.
The holes are 24, 30, 36 and 48 and this is a ratio of 4, 5, 6, and 8. The combined sound of all 4 holes creating a siren sound is a natural musical chord.
For the blow tube only, see SW3770-001