The model of choice used in the IRB Rugby World Cup and most NRL (rugby league) referees. Large size, solid whistle with low to medium tone.

Made in UK - 130 years of whistle making experience
Tapered mouthpiece design
Great versality with whistle sound and loudness
Waterproof speed pea with easy-to-blow, instant response which doesn't lose intensity when growing wet with saliva
Natural cork ball helps the whistle emit a highly audible trill to get the attention of players or spectators
Unbeatable in strong winds and easily heard because of fluctuating

Acme 58.5 Thunderer Whistle