Word meaning vulnerable to the elements

Question

I would like to see what is the closest word I can get that means vulnerable to the elements. One word is preferred, as opposed to a phrase. Here is a basic example:

Steel is ____________, but titanium is not ____________.

Ideally the word is not only relevant to corrosion like in the above example, but also other elements, whatever they may be (sunlight, wind, cold, ect)

Chemlights are ____________, but flashlights are not ____________.

(in the 2nd example the element implied is sunlight. Sunlight will degrade the chemlight, but will not impact the flashlight's performance -- not that you would use a flashlight on a sunny day, assumed you used at a later date at night after exposure to sunlight)

Answer 1

could you be looking for pervious and impervious?

As adjectives the difference between pervious and impervious is that pervious is admitting passage; capable of being penetrated by another body or substance; permeable while impervious is unaffected or unable to be affected by.

or simply

Weatherproof

Resistant to the effects of bad weather, especially rain.

Answer 2

susceptible works, although that doesn't exclusively refer to susceptibility to the elements.

From Merriam Webster:

susceptible - adjective - sus·cep·ti·ble \ sə-ˈsep-tə-bəl \ - 1 : capable of submitting to an action, process, or operation a theory susceptible to proof

2 : open, subject, or unresistant to some stimulus, influence, or agency susceptible to pneumonia

3 : impressionable, responsive a susceptible mind

— susceptibleness noun

— susceptibly adverb