The difference between human and pet meters is close at lower levels and further apart at higher levels. Normal on a human meter is 50-120 and on a pet meter it's 68-150. So while a 50 on a human meter is about a 70 on a pet meter, only 20 apart... A 300 on a human meter could be a 400 on an Alphatrak. Either way you will know if your cat is too low or high.