# DIMBLK1 System Variable [GstarCAD 2020](Help%20System/GSTARCAD/2020/Index.md) → [System Variables](Help%20System/GSTARCAD/2020/System%20Variables/(System%20Variables).md) → [D](Help%20System/GSTARCAD/2020/System%20Variables/D/(D).md) **Function Description:** The DIMBLK1 system variable is used to set arrowhead for the first end of extension line when the DIMSAH is on. | | | | --- | --- | | Type | Strings | | Saved in | Drawing | | Initial value | "" | Users could enter a Period "." to restore default settings. **Note:** the annotative block could not be used as customized arrow for dimensions and leaders. --- ## Other versions with matching text [GstarCAD 2016](../../../2016/System%20Variables/D/DIMBLK1%20System%20Variable--4162769e2742.md) · [GstarCAD 2017](../../../2017/System%20Variables/D/DIMBLK1%20System%20Variable--4162769e2742.md) · [GstarCAD 2018](../../../2018/System%20Variables/D/DIMBLK1%20System%20Variable--4162769e2742.md) · [GstarCAD 2019](../../../2019/System%20Variables/D/DIMBLK1%20System%20Variable--4162769e2742.md) · [GstarCAD 2021](../../../2021/System%20Variables/D/DIMBLK1%20System%20Variable--4162769e2742.md)