War nickels were produced in the US during World War II when demand for copper and nickel compelled the US Mint to save some nickel by adding 35% silver by weight to the coin.
Each nickel is roughly 1/9th troy ounces silver, so more divisible than a silver quarter (0.179 oz) but less divisible than a dime (1/14th oz).
War nickels are easy to identify by either looking at the dates (1942-1945), or looking for a mint mark above the dome (P, D, or S), no mint mark means it's a regular non-silver nickel.
War nickels have often sold close to spot price, but with premiums so high lately, these can be a good way to get a divisible barter form of silver @ $1.50/oz over spot.
https://monumentmetals.com/wartime-nickel-1-face-value.html