Lads I have bit of a problem here so if their is is any sportdog collar owners on here please put me straight I originally had a canicom 400 collar and reciever which is great no problem bar the led screen is a bit scary showing the digits on it but totally my fault due to the battering it has got over the year but I wanted to add a extra collar to the set up for another dog but I could not get one anywhere which brings me on to the sportdog 425sd I purchased this unit barking in mind it was not cheap + addtional collar so I can keep my two dogs in check so I open the box and try and match the