Shrink-2-Fit or Shrink-2-Fit Lite Dont guess how hot to heat couplings, bearings, or other shaft fitments. Shrink-2-Fit is designed to assist the mechanic with the installation of coupling, bearings, or other shaft fitments that require thermal growth to overcome interference fits. Features include; - Key length calculator, used to determine optimal length of key stock for coupling fitments. - Fitment thermal growth calculator, used to determine the correct temperature to heat the fitment, slide it on the shaft, and position it to the correct location with confidence. - Imperial or Metric units