# DIMBLK1 System Variable [GstarCAD 2027](Help%20System/GSTARCAD/2027/Index.md) → [System Variables](Help%20System/GSTARCAD/2027/System%20Variables/(System%20Variables).md) → [D](Help%20System/GSTARCAD/2027/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 can enter a Period "." to restore default settings. **Note:** the annotative block can not be used as customized arrow for dimensions and leaders. --- [Original help](https://www.gstarcad.net/help/GstarCAD_2027_en-US/detail/systemVariables_Dgsv/DIMBLK1.html) · © Gstarsoft Co., Ltd.