12 PROPANE GAS FIRED ENGINE HEATERS; ELECTRIC STOCK TANK HEATERS; ELECTRICAL STARTING AID KITS INCLUDING A BATTERY WARMER, OIL PAN HEATER, TANK HEATER, ELECTRICAL COOLANT CIRCULATING PUMP, JUNCTION BLOCK WITH WEATHERPROOF SLAVE RECEPTACLE, AND CONNECTING CABLE; ELECTRICAL AND MANUAL STARTING FLUID INJECTORS FOR INJECTING METERED VOLUMES OF ETHER OR THE LIKE INTO THE INTAKE MANIFOLD OF AN ENGINE; ELECTRIC DIP STICK HEATERS; ELECTRIC HEAD-BOLT HEATERS; ELECTRIC FROST PLUG HEATERS; ELECTRIC EXTERNAL TANK TYPE HEATERS; ELECTRIC OIL PAN HEATERS; ELECTRIC DIESEL ENGINE BLOCK HEATERS; ELECTRIC BATTERY WARMERS; AND ENGINE STARTERS AND STANDBY UNITS-NAMELY, PORTABLE ELECTRICAL BOOSTER UNITS, PORTABLE BATTERY BOOSTING AND CHARGING UNITS, GAS ENGINE DRIVEN ELECTRICAL STARTERS, AND COMBINED AC/DC STARTER AND STANDBY GENERATORS