ACA4450. 400 (rpm) Free Speed. OSHA approved Quiet Technology 85 dBa. Lightweight at only 3.0 lbs. Ergonomic handle design to relieve stress and fatigue on the operator’s hands. Composite red housing. AIRCAT® offers another "Silent Power" product for the shop or home. The AIRCAT® 4450 1/2" Reversible Red Composite Drill, gives the user 400 (rpm) Free Speed while only producing 85 dBa. so you can work without the noise.