You are assigned a cargo tank commonly used to haul propane. Which specification tank is this most likely to be, and what does the other common specification typically carry?

AAMVA CDL Manual Sec 9.5 (nhcdm.pdf p.9-12)

Knowing which cargo tank specification you are hauling tells you what product category and hazard profile to expect before you even check the shipping papers. Liquid tankers and pressurized-gas tankers have different loading, venting, and emergency procedures, and mixing up which is which during an emergency response could lead to the wrong safety action.