Silver futures
Silver futures are contracts that let businesses agree to buy or sell silver at some point in the future. Though they're often a hedging tool, investors and traders can use futures contracts to speculate on silver price movements.
Silver futures are standardized contracts traded on exchanges such as the COMEX (part of the CME Group). Each contract represents 5,000 troy ounces of silver, though micro silver futures offer a smaller contract size of 1,000 ounces.
Since futures use leverage, they can lead to big gains or big losses, depending on how the market moves. You'll only put down a small percentage of the contract's value through a margin deposit. For example, if silver is trading at $40/ounce, a standard futures contract would cost $200,000 ($40*5,000 troy ounces), but you might only need an initial margin deposit of $15,000.
However, if the price moves against your position, you may face a margin call. You'd need to deposit additional funds -- otherwise, your broker could liquidate your position, and you'd still be responsible for any amount you owe.