Markal Silver-Streak Reflective Round Refills are designed to be used with Markal Silver-Streak holder (item# 96006), also called a mechanical pencil. Markal Silver-Streak holder is an all-purpose marker for cold surfaces that will mark any material surface or texture. Use under any conditions such as oily, rough, smooth, wet, dry, icy, or rusty surfaces. These refills can be used for layout work on sheet metal, pipe layout, and plasma cutting. You can mark thin lines for accurate measurements and mark lines won't burn off when using a plasma or acetylene torch. The Markal Silver Streak holder with refills performs better than chalk or soapstone. The six refills come in a nice protective case to protect them from breaking.