STIHL RMA 510 V 21 in. 36 V Battery Self Propelled Lawn Mower Kit (Battery & Charger) Roll Out Drawer 400 RPM and 0 BPM 400 RPM and 0 BPM to 4 Eco Friendly Certification: FloorScore Indoor Air Quality Certified for healthier living environments Locking key key prevents accidental starting of the motor 36 V Battery Self Propelled Feature 10 Text Feature 1 Text Self propelled with variable speed drive a squee Feature 2 Text Brushless electric motor with ECO mode the motor Feature 3 Text Zero or low exhaust emissions Feature 4 Text Mower can be stowed in three positions: folded or Feature 5 Text Locking key key prevents accidental starting of Feature 6 Text No gradual drop in power