uxcell US Plug to Outlet Power Extension Cord Cable 13A 16AWG SJTW 50Ft NEMA 5-15P to NEMA 5-15R Black

Features:
* 16 gauge, 3-Prong plug cord
* 50 feet long, heavy-duty
* 16/3 cords, 13A, 125V, 1625W, 60Hz
* Wires are double coated with a thick rubber-like insulation, offering kink-free flexibility - cables are flexible even in cold weather.
* Weather resistant: will not be affected by weather temperature variations.

Will this cord do well in the rain?
Answer: The SJTW in the description of the product describes how it should be used.
S means that this cord is rated for Hard Service, J means it is rated for up to 300Volts (though this is just a rating and will be plugged in to a 125 Volt home outlet), T means the coating is Thermoplastic, and W means it is rated for Weather/Outdoor Use. If connected properly and the ends are shielded from direct water penetration then yes, this cord should work well in the rain as it is rated for it.

How many continuous amps can this carry?
Answer: It is rated at 13A, 125 volts and 1625 watts

Is this extension cord suitable for Car block heaters. i have small plug from car heater out and need an extension cord to connect with electricity?
Answer: It depends on how much power your car heater uses. This is a 16AWG cord, which can carry 13A without overheating. If your heater has a standard 3-prong plug then it draws less than 13A so you should be fine with this cord.