210: High pitch, quiet to users, fitted with a weatherproof pea. A great whistle for close work and a different style of sound for a different command
210.5: High pitch, quiet to the user and preferred by Spaniel owners but an excellent all-round dog whistle for close and distance control. This whistle is recommended for both use in Town and the Countryside
211.5: Medium high pitch, single note, preferred by Labrador and Retriever trainers; good distance whistle.
575 Shepherds Whistle: Enables the dog trainer to create a crescendo of sound in tremendous variety. There are many dog trainers who consider this to be the ultimate in-tune communication with your dog.