•Whistle had Adjustable Frequency
•Protective end cap
•Quiet human audible sound to confirm whistle is working
•However the whistle is engineered to produce a relatively quiet whistle sound audible in the human range the sole purpose of this is to reassure the user that a sound in the required range is being produced
•The reason for this is that if the whistle is incorrectly set up when selecting the frequency then it will not function properly without this facility the user will not realise the whistle is not working