We got a rescue Sheltie recently and, when calling her in from the garden, I realised she responded well to me whistling - bad though my whistling is. Tammy is an oversized, rangy, very athletic Sheltie so I also realised that I'd need to have a good recall. I put two and two together, researched whistles, found Logan Whistles and bought the A1. I started practising and took a tip from the reviewer who practised in their car so 100+ commuting miles later and I can whistle a recall. It's an amazing piece of kit and Tammy responds instantaneously. This past week with strong winds It's been invaluable - my voice would not carry into the wind I bought one for my husband, hes currently learning and is equally impressed. Then I treated my best friend - and her recalcitrant red fox lab - to the starter kit. Di Is having great fun learning to use her Logan Whistle; Di and I both get the best sounds when we hold it upside down. So it's five stars from us all.