Fluid delivery device for discharging a fluid, having: a housing； piston pump； biasing mechanism； and trigger mechanism. The housing has a basal end and a discharge end with outlet for discharging the fluid. The piston pump has a casing defining a pump chamber for storage of fluid, a piston slidably movable relative to the pump chamber, a piston plunger, and a delivery channel. The trigger mechanism is movable from a cocked configuration wherein the trigger mechanism prevents transfer of a biasing force of the biasing mechanism to the casing to a triggered configuration with the trigger mechanism enabling transfer of the biasing force to the casing to cause movement of the casing towards the housing outlet to discharge fluid from the pump chamber, along the delivery channel and out of the outlet of the housing. The biasing mechanism has one or more flexible catch members and a manually operable trigger.
