RE: Sportdog 1200
the size of the box will not brother the dogs. we use the 2400 models on our beagles with no problems. they have the same size box. just set the collar to hold the box on side of the neck just under the ear. if the collar is not tight on their neck you can push the button all day long and they will not receive anything. it has to be touching at all times. if the collar has a warning mode always use that before you shock. it will only be a few days and the warning will be all you need to use. and never set the shock up any higher than you can take on your own fingers. any higher than that and you could ruin your dog.