These blowguns are some of the best I've used. When looking for which to buy, consider these points:

Prevost Metal Nozzle Blow Gun: These are your normal everyday blowguns. They have a short metal tip and can take any 1/4" NPT threaded connection.

Prevost 13" Bent Metal Nozzle Blow Gun: These are for hard-to-reach places and have a bent 13" metal tip for those times when you don't feel like bending down. These can take any 1/4" NPT threaded connection.

Prevost Non-Scratch Blow Gun: These are for blowing out areas that you're worried about possibly damaging with a normal metal nozzle blowgun. These have a polyamide composite body and tip and can take any 1/4" NPT threaded connection.

Specifications

Prevost Metal Nozzle Blow Gun:

• Blowing force (at 87 psi): 13 oz. 
• Air consumption (at 87 psi): 13.5 SCFM
• Noise Level (at 87 psi): 83 dBA

Prevost 13" Bent Metal Nozzle Blow Gun:

• Blowing force (at 87 psi): 9.3 oz. 
• Air consumption (at 87 psi): 8.8 SCFM
• Noise Level (at 87 psi): 86 dBA

Prevost Non-Scratch Blow Gun:

• Blowing force (at 87 psi): 11 oz.
• Air consumption (at 87 psi): 7.2 SCFM
• Noise Level (at 87 psi): 84 dBA