The electorate in Northern Ireland will head to polling stations to cast their vote in the Assembly election on Thursday, May 5.
But why is it only pencils that are available to voters (often attached on a length of string in the polling booth) when they write down their voting preferences? The Electoral Office for Northern Ireland has explained why.
It said pencils are used as they are less likely to tear the ballot paper, and have been considered cheaper as well as easier to store between elections.
Read more: Click here for comprehensive election coverage
As well as this, pencils are typically used at the polls around the UK as if a pen mark spills over a paper, it could invalidate a person's vote.
Previously, the Electoral Commission has argued that the use of pencils does not itself increase the likelihood of electoral fraud, adding that: "while pencil marks can be rubbed out, similarly, pen marks can be crossed out."
Tampering with ballot papers is a serious offence and if anyone has evidence that ballot papers have been tampered with, they should report it to police.
And despite all this, if you wish to cast your vote using your own pen - you can.
Follow live: Updates as voters go to the polls
Read more: NI election: Every candidate running for the Assembly
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