To adjust and switch a delivery amount without changing the hold of a dispenser.

The pneumatic dispenser for dispensing viscous material, for example, mastic caulk, from a container is described. The dispenser includes a fluid supply device for accepting a dispensing nozzle of the container and providing a flow of pressurized fluid to the dispensing nozzle to enable the material to be dispensed as a spray. A moveable member can be used to control the flow of pressurized fluid, for example a member disposed on a cap for closing a container containing compartment of the dispenser and/or a moveable member disposed around the dispensing nozzle. The structure of the fluid supply device allows for convenient control of the pressurized fluid flow for spraying the material. There is also disclosed a dispenser with a readily exchangeable pressure application interface for applying a dispensing pressure to the container, enabling the dispenser to be used with both cartridge and foil pack containers.