The Scotty 4000 pump is a single action pump.  The pump has a brass pump chamber protected by an engineering grade polymer sleeve.  No tools are required to disassemble the unit, it can be completely disassembled by hand for in-the-field maintenance.

(See the diagram on page 14 for pump parts and check valve assembly)

Check valve replacement kit (FP-REPAIRKIT)

The Back Pack (4002A) has a capacity of 5 US gallons (19 litres).  Manufactured from a strong polyester reinfirced fabric, protected by a thermoplastic polymer layer.  It has a 4” filler port with a removable debris screen, 2” wide shoulder straps and 3” wide shoulder pads.

(Meets UL and other back pack pump specifications)