Allegro Single Worker Ambient Fresh Air System Allegro Safety is top of the line for all of your fresh air breathing products. Ideal for a super portable, lightweight air source for a single respirator user. Includes (1) 1/4 HP Fresh Air Pump, (1) Full Face Mask Respirator, (100') Fresh Air Hose. This unit is ideal for many applications. Works great for the Spray Foam Insulation contractor.