Latex
Amber, 40 durometer Also Available in Colors
Neoprene
Black, 60 durometer. (CR) Chloroprene. The material for Freon. Beyond that it is usually a best "second" choice and to be considered when there is a combination of media.
PTFE
(PTFE) Polytetrafluoroethylene. A synthetic fluoropolymer of tetrafluoroethylene that has numerous applications.
Pure Gum
45 durometer, T=Tan B=Black R=Red
PVC
Clear, Flexible
Silicone
60 durometer, Red or Translucent. An inorganic material, broadest temp range ( -100°F to +500°F). Great for aging. medical grades, FDA grades, colors. Not the best physical properties. Poor oil resistance.