I like that carpet mill (or belt mill) a lot. It is very smooth in operation. The carpet/belt does not bind up or lift as the dog pulls/pushes with each stride. Very important. Lots of carpet mills ride up or bunch, especially on the more powerful rear leg strides, and the dog has to adjust his next step to compensate for the ever changing running surface. Free seems to be the word in slat mills but I think smooth is the word for carpet/belt type mills. If it is a smooth turning mill then the level of free-ness coupled with the conditioning of the dog will determine times. EWO