A catheter produced for use in a medical device must meet exacting specs: 2.45 mm plus or minus 0.05 mm on its outside diameter (OD). The catheter is made via an extrusion process, which is based on three factors: A, extruder feed rate: 900-1,100 gr/hr; B, zone-1 temperature, 165-195 oC; and C, raw material supplier: Acme (-1) or Ecma (+1). The RSM design chosen follows: