A fluid dispensing device having a barrel having a lumen for containing a fluid therein and a flexible structure extending from the barrel. A plunger is axially slidable within the lumen to dispense fluid from the barrel, the plunger having a first set of grooves spaced apart a first distance and a second set of grooves spaced apart a second distance. The flexible structure includes a flexible arm extending transversely with respect to the barrel and configured to engage the grooves.