An apparatus for forming a hem is provided. The snowmobile further includes a plurality of ground-engaging members cooperating with the power train unit to operate the snowmobile. A jitter equalizer may be coupled with the data path andor clock path to provide a programmable delay to the data signal andor clock signal, respectively. coli are retained in the reactor by micro or ultrafiltration membranes which are arranged as a flat membrane module or hollow fiber module.